1 | /* |
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2 | * Itanium 2-optimized version of memcpy and copy_user function |
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3 | * |
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4 | * Inputs: |
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5 | * in0: destination address |
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6 | * in1: source address |
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7 | * in2: number of bytes to copy |
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8 | * Output: |
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9 | * 0 if success, or number of byte NOT copied if error occurred. |
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10 | * |
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11 | * Copyright (C) 2002 Intel Corp. |
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12 | * Copyright (C) 2002 Ken Chen <kenneth.w.chen@intel.com> |
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13 | */ |
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14 | #include <linux/config.h> |
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15 | #include <asm/asmmacro.h> |
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16 | #include <asm/page.h> |
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17 | |
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18 | #define EK(y...) EX(y) |
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19 | |
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20 | /* McKinley specific optimization */ |
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21 | |
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22 | #define retval r8 |
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23 | #define saved_pfs r31 |
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24 | #define saved_lc r10 |
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25 | #define saved_pr r11 |
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26 | #define saved_in0 r14 |
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27 | #define saved_in1 r15 |
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28 | #define saved_in2 r16 |
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29 | |
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30 | #define src0 r2 |
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31 | #define src1 r3 |
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32 | #define dst0 r17 |
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33 | #define dst1 r18 |
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34 | #define cnt r9 |
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35 | |
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36 | /* r19-r30 are temp for each code section */ |
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37 | #define PREFETCH_DIST 8 |
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38 | #define src_pre_mem r19 |
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39 | #define dst_pre_mem r20 |
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40 | #define src_pre_l2 r21 |
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41 | #define dst_pre_l2 r22 |
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42 | #define t1 r23 |
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43 | #define t2 r24 |
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44 | #define t3 r25 |
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45 | #define t4 r26 |
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46 | #define t5 t1 // alias! |
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47 | #define t6 t2 // alias! |
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48 | #define t7 t3 // alias! |
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49 | #define n8 r27 |
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50 | #define t9 t5 // alias! |
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51 | #define t10 t4 // alias! |
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52 | #define t11 t7 // alias! |
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53 | #define t12 t6 // alias! |
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54 | #define t14 t10 // alias! |
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55 | #define t13 r28 |
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56 | #define t15 r29 |
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57 | #define tmp r30 |
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58 | |
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59 | /* defines for long_copy block */ |
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60 | #define A 0 |
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61 | #define B (PREFETCH_DIST) |
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62 | #define C (B + PREFETCH_DIST) |
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63 | #define D (C + 1) |
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64 | #define N (D + 1) |
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65 | #define Nrot ((N + 7) & ~7) |
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66 | |
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67 | /* alias */ |
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68 | #define in0 r32 |
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69 | #define in1 r33 |
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70 | #define in2 r34 |
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71 | |
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72 | GLOBAL_ENTRY(memcpy) |
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73 | and r28=0x7,in0 |
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74 | and r29=0x7,in1 |
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75 | mov f6=f0 |
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76 | br.cond.sptk .common_code |
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77 | ;; |
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78 | END(memcpy) |
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79 | GLOBAL_ENTRY(__copy_user) |
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80 | .prologue |
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81 | // check dest alignment |
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82 | and r28=0x7,in0 |
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83 | and r29=0x7,in1 |
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84 | mov f6=f1 |
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85 | mov saved_in0=in0 // save dest pointer |
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86 | mov saved_in1=in1 // save src pointer |
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87 | mov saved_in2=in2 // save len |
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88 | ;; |
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89 | .common_code: |
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90 | cmp.gt p15,p0=8,in2 // check for small size |
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91 | cmp.ne p13,p0=0,r28 // check dest alignment |
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92 | cmp.ne p14,p0=0,r29 // check src alignment |
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93 | add src0=0,in1 |
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94 | sub r30=8,r28 // for .align_dest |
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95 | mov retval=r0 // initialize return value |
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96 | ;; |
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97 | add dst0=0,in0 |
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98 | add dst1=1,in0 // dest odd index |
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99 | cmp.le p6,p0 = 1,r30 // for .align_dest |
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100 | (p15) br.cond.dpnt .memcpy_short |
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101 | (p13) br.cond.dpnt .align_dest |
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102 | (p14) br.cond.dpnt .unaligned_src |
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103 | ;; |
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104 | |
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105 | // both dest and src are aligned on 8-byte boundary |
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106 | .aligned_src: |
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107 | .save ar.pfs, saved_pfs |
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108 | alloc saved_pfs=ar.pfs,3,Nrot-3,0,Nrot |
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109 | .save pr, saved_pr |
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110 | mov saved_pr=pr |
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111 | |
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112 | shr.u cnt=in2,7 // this much cache line |
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113 | ;; |
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114 | cmp.lt p6,p0=2*PREFETCH_DIST,cnt |
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115 | cmp.lt p7,p8=1,cnt |
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116 | .save ar.lc, saved_lc |
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117 | mov saved_lc=ar.lc |
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118 | .body |
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119 | add cnt=-1,cnt |
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120 | add src_pre_mem=0,in1 // prefetch src pointer |
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121 | add dst_pre_mem=0,in0 // prefetch dest pointer |
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122 | ;; |
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123 | (p7) mov ar.lc=cnt // prefetch count |
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124 | (p8) mov ar.lc=r0 |
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125 | (p6) br.cond.dpnt .long_copy |
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126 | ;; |
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127 | |
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128 | .prefetch: |
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129 | lfetch.fault [src_pre_mem], 128 |
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130 | lfetch.fault.excl [dst_pre_mem], 128 |
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131 | br.cloop.dptk.few .prefetch |
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132 | ;; |
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133 | |
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134 | .medium_copy: |
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135 | and tmp=31,in2 // copy length after iteration |
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136 | shr.u r29=in2,5 // number of 32-byte iteration |
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137 | add dst1=8,dst0 // 2nd dest pointer |
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138 | ;; |
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139 | add cnt=-1,r29 // ctop iteration adjustment |
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140 | cmp.eq p10,p0=r29,r0 // do we really need to loop? |
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141 | add src1=8,src0 // 2nd src pointer |
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142 | cmp.le p6,p0=8,tmp |
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143 | ;; |
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144 | cmp.le p7,p0=16,tmp |
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145 | mov ar.lc=cnt // loop setup |
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146 | cmp.eq p16,p17 = r0,r0 |
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147 | mov ar.ec=2 |
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148 | (p10) br.dpnt.few .aligned_src_tail |
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149 | ;; |
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150 | TEXT_ALIGN(32) |
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151 | 1: |
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152 | EX(.ex_handler, (p16) ld8 r34=[src0],16) |
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153 | EK(.ex_handler, (p16) ld8 r38=[src1],16) |
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154 | EX(.ex_handler, (p17) st8 [dst0]=r33,16) |
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155 | EK(.ex_handler, (p17) st8 [dst1]=r37,16) |
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156 | ;; |
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157 | EX(.ex_handler, (p16) ld8 r32=[src0],16) |
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158 | EK(.ex_handler, (p16) ld8 r36=[src1],16) |
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159 | EX(.ex_handler, (p16) st8 [dst0]=r34,16) |
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160 | EK(.ex_handler, (p16) st8 [dst1]=r38,16) |
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161 | br.ctop.dptk.few 1b |
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162 | ;; |
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163 | |
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164 | .aligned_src_tail: |
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165 | EX(.ex_handler, (p6) ld8 t1=[src0]) |
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166 | mov ar.lc=saved_lc |
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167 | mov ar.pfs=saved_pfs |
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168 | EX(.ex_hndlr_s, (p7) ld8 t2=[src1],8) |
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169 | cmp.le p8,p0=24,tmp |
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170 | and r21=-8,tmp |
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171 | ;; |
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172 | EX(.ex_hndlr_s, (p8) ld8 t3=[src1]) |
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173 | EX(.ex_handler, (p6) st8 [dst0]=t1) // store byte 1 |
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174 | and in2=7,tmp // remaining length |
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175 | EX(.ex_hndlr_d, (p7) st8 [dst1]=t2,8) // store byte 2 |
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176 | add src0=src0,r21 // setting up src pointer |
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177 | add dst0=dst0,r21 // setting up dest pointer |
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178 | ;; |
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179 | EX(.ex_handler, (p8) st8 [dst1]=t3) // store byte 3 |
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180 | mov pr=saved_pr,-1 |
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181 | br.dptk.many .memcpy_short |
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182 | ;; |
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183 | |
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184 | /* code taken from copy_page_mck */ |
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185 | .long_copy: |
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186 | .rotr v[2*PREFETCH_DIST] |
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187 | .rotp p[N] |
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188 | |
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189 | mov src_pre_mem = src0 |
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190 | mov pr.rot = 0x10000 |
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191 | mov ar.ec = 1 // special unrolled loop |
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192 | |
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193 | mov dst_pre_mem = dst0 |
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194 | |
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195 | add src_pre_l2 = 8*8, src0 |
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196 | add dst_pre_l2 = 8*8, dst0 |
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197 | ;; |
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198 | add src0 = 8, src_pre_mem // first t1 src |
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199 | mov ar.lc = 2*PREFETCH_DIST - 1 |
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200 | shr.u cnt=in2,7 // number of lines |
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201 | add src1 = 3*8, src_pre_mem // first t3 src |
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202 | add dst0 = 8, dst_pre_mem // first t1 dst |
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203 | add dst1 = 3*8, dst_pre_mem // first t3 dst |
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204 | ;; |
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205 | and tmp=127,in2 // remaining bytes after this block |
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206 | add cnt = -(2*PREFETCH_DIST) - 1, cnt |
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207 | // same as .line_copy loop, but with all predicated-off instructions removed: |
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208 | .prefetch_loop: |
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209 | EX(.ex_hndlr_lcpy_1, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 |
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210 | EK(.ex_hndlr_lcpy_1, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 |
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211 | br.ctop.sptk .prefetch_loop |
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212 | ;; |
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213 | cmp.eq p16, p0 = r0, r0 // reset p16 to 1 |
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214 | mov ar.lc = cnt |
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215 | mov ar.ec = N // # of stages in pipeline |
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216 | ;; |
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217 | .line_copy: |
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218 | EX(.ex_handler, (p[D]) ld8 t2 = [src0], 3*8) // M0 |
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219 | EK(.ex_handler, (p[D]) ld8 t4 = [src1], 3*8) // M1 |
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220 | EX(.ex_handler_lcpy, (p[B]) st8 [dst_pre_mem] = v[B], 128) // M2 prefetch dst from memory |
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221 | EK(.ex_handler_lcpy, (p[D]) st8 [dst_pre_l2] = n8, 128) // M3 prefetch dst from L2 |
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222 | ;; |
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223 | EX(.ex_handler_lcpy, (p[A]) ld8 v[A] = [src_pre_mem], 128) // M0 prefetch src from memory |
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224 | EK(.ex_handler_lcpy, (p[C]) ld8 n8 = [src_pre_l2], 128) // M1 prefetch src from L2 |
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225 | EX(.ex_handler, (p[D]) st8 [dst0] = t1, 8) // M2 |
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226 | EK(.ex_handler, (p[D]) st8 [dst1] = t3, 8) // M3 |
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227 | ;; |
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228 | EX(.ex_handler, (p[D]) ld8 t5 = [src0], 8) |
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229 | EK(.ex_handler, (p[D]) ld8 t7 = [src1], 3*8) |
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230 | EX(.ex_handler, (p[D]) st8 [dst0] = t2, 3*8) |
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231 | EK(.ex_handler, (p[D]) st8 [dst1] = t4, 3*8) |
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232 | ;; |
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233 | EX(.ex_handler, (p[D]) ld8 t6 = [src0], 3*8) |
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234 | EK(.ex_handler, (p[D]) ld8 t10 = [src1], 8) |
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235 | EX(.ex_handler, (p[D]) st8 [dst0] = t5, 8) |
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236 | EK(.ex_handler, (p[D]) st8 [dst1] = t7, 3*8) |
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237 | ;; |
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238 | EX(.ex_handler, (p[D]) ld8 t9 = [src0], 3*8) |
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239 | EK(.ex_handler, (p[D]) ld8 t11 = [src1], 3*8) |
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240 | EX(.ex_handler, (p[D]) st8 [dst0] = t6, 3*8) |
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241 | EK(.ex_handler, (p[D]) st8 [dst1] = t10, 8) |
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242 | ;; |
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243 | EX(.ex_handler, (p[D]) ld8 t12 = [src0], 8) |
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244 | EK(.ex_handler, (p[D]) ld8 t14 = [src1], 8) |
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245 | EX(.ex_handler, (p[D]) st8 [dst0] = t9, 3*8) |
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246 | EK(.ex_handler, (p[D]) st8 [dst1] = t11, 3*8) |
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247 | ;; |
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248 | EX(.ex_handler, (p[D]) ld8 t13 = [src0], 4*8) |
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249 | EK(.ex_handler, (p[D]) ld8 t15 = [src1], 4*8) |
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250 | EX(.ex_handler, (p[D]) st8 [dst0] = t12, 8) |
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251 | EK(.ex_handler, (p[D]) st8 [dst1] = t14, 8) |
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252 | ;; |
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253 | EX(.ex_handler, (p[C]) ld8 t1 = [src0], 8) |
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254 | EK(.ex_handler, (p[C]) ld8 t3 = [src1], 8) |
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255 | EX(.ex_handler, (p[D]) st8 [dst0] = t13, 4*8) |
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256 | EK(.ex_handler, (p[D]) st8 [dst1] = t15, 4*8) |
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257 | br.ctop.sptk .line_copy |
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258 | ;; |
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259 | |
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260 | add dst0=-8,dst0 |
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261 | add src0=-8,src0 |
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262 | mov in2=tmp |
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263 | .restore sp |
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264 | br.sptk.many .medium_copy |
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265 | ;; |
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266 | |
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267 | #define BLOCK_SIZE 128*32 |
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268 | #define blocksize r23 |
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269 | #define curlen r24 |
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270 | |
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271 | // dest is on 8-byte boundary, src is not. We need to do |
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272 | // ld8-ld8, shrp, then st8. Max 8 byte copy per cycle. |
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273 | .unaligned_src: |
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274 | .prologue |
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275 | .save ar.pfs, saved_pfs |
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276 | alloc saved_pfs=ar.pfs,3,5,0,8 |
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277 | .save ar.lc, saved_lc |
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278 | mov saved_lc=ar.lc |
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279 | .save pr, saved_pr |
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280 | mov saved_pr=pr |
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281 | .body |
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282 | .4k_block: |
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283 | mov saved_in0=dst0 // need to save all input arguments |
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284 | mov saved_in2=in2 |
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285 | mov blocksize=BLOCK_SIZE |
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286 | ;; |
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287 | cmp.lt p6,p7=blocksize,in2 |
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288 | mov saved_in1=src0 |
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289 | ;; |
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290 | (p6) mov in2=blocksize |
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291 | ;; |
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292 | shr.u r21=in2,7 // this much cache line |
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293 | shr.u r22=in2,4 // number of 16-byte iteration |
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294 | and curlen=15,in2 // copy length after iteration |
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295 | and r30=7,src0 // source alignment |
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296 | ;; |
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297 | cmp.lt p7,p8=1,r21 |
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298 | add cnt=-1,r21 |
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299 | ;; |
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300 | |
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301 | add src_pre_mem=0,src0 // prefetch src pointer |
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302 | add dst_pre_mem=0,dst0 // prefetch dest pointer |
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303 | and src0=-8,src0 // 1st src pointer |
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304 | (p7) mov ar.lc = cnt |
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305 | (p8) mov ar.lc = r0 |
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306 | ;; |
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307 | TEXT_ALIGN(32) |
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308 | 1: lfetch.fault [src_pre_mem], 128 |
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309 | lfetch.fault.excl [dst_pre_mem], 128 |
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310 | br.cloop.dptk.few 1b |
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311 | ;; |
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312 | |
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313 | shladd dst1=r22,3,dst0 // 2nd dest pointer |
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314 | shladd src1=r22,3,src0 // 2nd src pointer |
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315 | cmp.eq p8,p9=r22,r0 // do we really need to loop? |
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316 | cmp.le p6,p7=8,curlen; // have at least 8 byte remaining? |
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317 | add cnt=-1,r22 // ctop iteration adjustment |
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318 | ;; |
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319 | EX(.ex_handler, (p9) ld8 r33=[src0],8) // loop primer |
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320 | EK(.ex_handler, (p9) ld8 r37=[src1],8) |
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321 | (p8) br.dpnt.few .noloop |
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322 | ;; |
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323 | |
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324 | // The jump address is calculated based on src alignment. The COPYU |
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325 | // macro below need to confine its size to power of two, so an entry |
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326 | // can be caulated using shl instead of an expensive multiply. The |
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327 | // size is then hard coded by the following #define to match the |
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328 | // actual size. This make it somewhat tedious when COPYU macro gets |
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329 | // changed and this need to be adjusted to match. |
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330 | #define LOOP_SIZE 6 |
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331 | 1: |
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332 | mov r29=ip // jmp_table thread |
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333 | mov ar.lc=cnt |
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334 | ;; |
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335 | add r29=.jump_table - 1b - (.jmp1-.jump_table), r29 |
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336 | shl r28=r30, LOOP_SIZE // jmp_table thread |
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337 | mov ar.ec=2 // loop setup |
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338 | ;; |
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339 | add r29=r29,r28 // jmp_table thread |
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340 | cmp.eq p16,p17=r0,r0 |
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341 | ;; |
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342 | mov b6=r29 // jmp_table thread |
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343 | ;; |
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344 | br.cond.sptk.few b6 |
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345 | |
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346 | // for 8-15 byte case |
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347 | // We will skip the loop, but need to replicate the side effect |
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348 | // that the loop produces. |
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349 | .noloop: |
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350 | EX(.ex_handler, (p6) ld8 r37=[src1],8) |
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351 | add src0=8,src0 |
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352 | (p6) shl r25=r30,3 |
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353 | ;; |
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354 | EX(.ex_handler, (p6) ld8 r27=[src1]) |
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355 | (p6) shr.u r28=r37,r25 |
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356 | (p6) sub r26=64,r25 |
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357 | ;; |
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358 | (p6) shl r27=r27,r26 |
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359 | ;; |
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360 | (p6) or r21=r28,r27 |
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361 | |
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362 | .unaligned_src_tail: |
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363 | /* check if we have more than blocksize to copy, if so go back */ |
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364 | cmp.gt p8,p0=saved_in2,blocksize |
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365 | ;; |
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366 | (p8) add dst0=saved_in0,blocksize |
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367 | (p8) add src0=saved_in1,blocksize |
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368 | (p8) sub in2=saved_in2,blocksize |
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369 | (p8) br.dpnt .4k_block |
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370 | ;; |
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371 | |
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372 | /* we have up to 15 byte to copy in the tail. |
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373 | * part of work is already done in the jump table code |
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374 | * we are at the following state. |
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375 | * src side: |
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376 | * |
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377 | * xxxxxx xx <----- r21 has xxxxxxxx already |
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378 | * -------- -------- -------- |
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379 | * 0 8 16 |
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380 | * ^ |
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381 | * | |
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382 | * src1 |
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383 | * |
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384 | * dst |
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385 | * -------- -------- -------- |
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386 | * ^ |
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387 | * | |
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388 | * dst1 |
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389 | */ |
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390 | EX(.ex_handler, (p6) st8 [dst1]=r21,8) // more than 8 byte to copy |
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391 | (p6) add curlen=-8,curlen // update length |
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392 | mov ar.pfs=saved_pfs |
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393 | ;; |
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394 | mov ar.lc=saved_lc |
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395 | mov pr=saved_pr,-1 |
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396 | mov in2=curlen // remaining length |
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397 | mov dst0=dst1 // dest pointer |
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398 | add src0=src1,r30 // forward by src alignment |
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399 | ;; |
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400 | |
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401 | // 7 byte or smaller. |
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402 | .memcpy_short: |
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403 | cmp.le p8,p9 = 1,in2 |
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404 | cmp.le p10,p11 = 2,in2 |
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405 | cmp.le p12,p13 = 3,in2 |
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406 | cmp.le p14,p15 = 4,in2 |
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407 | add src1=1,src0 // second src pointer |
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408 | add dst1=1,dst0 // second dest pointer |
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409 | ;; |
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410 | |
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411 | EX(.ex_handler_short, (p8) ld1 t1=[src0],2) |
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412 | EK(.ex_handler_short, (p10) ld1 t2=[src1],2) |
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413 | (p9) br.ret.dpnt rp // 0 byte copy |
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414 | ;; |
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415 | |
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416 | EX(.ex_handler_short, (p8) st1 [dst0]=t1,2) |
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417 | EK(.ex_handler_short, (p10) st1 [dst1]=t2,2) |
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418 | (p11) br.ret.dpnt rp // 1 byte copy |
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419 | |
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420 | EX(.ex_handler_short, (p12) ld1 t3=[src0],2) |
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421 | EK(.ex_handler_short, (p14) ld1 t4=[src1],2) |
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422 | (p13) br.ret.dpnt rp // 2 byte copy |
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423 | ;; |
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424 | |
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425 | cmp.le p6,p7 = 5,in2 |
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426 | cmp.le p8,p9 = 6,in2 |
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427 | cmp.le p10,p11 = 7,in2 |
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428 | |
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429 | EX(.ex_handler_short, (p12) st1 [dst0]=t3,2) |
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430 | EK(.ex_handler_short, (p14) st1 [dst1]=t4,2) |
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431 | (p15) br.ret.dpnt rp // 3 byte copy |
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432 | ;; |
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433 | |
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434 | EX(.ex_handler_short, (p6) ld1 t5=[src0],2) |
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435 | EK(.ex_handler_short, (p8) ld1 t6=[src1],2) |
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436 | (p7) br.ret.dpnt rp // 4 byte copy |
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437 | ;; |
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438 | |
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439 | EX(.ex_handler_short, (p6) st1 [dst0]=t5,2) |
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440 | EK(.ex_handler_short, (p8) st1 [dst1]=t6,2) |
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441 | (p9) br.ret.dptk rp // 5 byte copy |
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442 | |
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443 | EX(.ex_handler_short, (p10) ld1 t7=[src0],2) |
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444 | (p11) br.ret.dptk rp // 6 byte copy |
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445 | ;; |
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446 | |
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447 | EX(.ex_handler_short, (p10) st1 [dst0]=t7,2) |
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448 | br.ret.dptk rp // done all cases |
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449 | |
---|
450 | |
---|
451 | /* Align dest to nearest 8-byte boundary. We know we have at |
---|
452 | * least 7 bytes to copy, enough to crawl to 8-byte boundary. |
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453 | * Actual number of byte to crawl depend on the dest alignment. |
---|
454 | * 7 byte or less is taken care at .memcpy_short |
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455 | |
---|
456 | * src0 - source even index |
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457 | * src1 - source odd index |
---|
458 | * dst0 - dest even index |
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459 | * dst1 - dest odd index |
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460 | * r30 - distance to 8-byte boundary |
---|
461 | */ |
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462 | |
---|
463 | .align_dest: |
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464 | add src1=1,in1 // source odd index |
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465 | cmp.le p7,p0 = 2,r30 // for .align_dest |
---|
466 | cmp.le p8,p0 = 3,r30 // for .align_dest |
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467 | EX(.ex_handler_short, (p6) ld1 t1=[src0],2) |
---|
468 | cmp.le p9,p0 = 4,r30 // for .align_dest |
---|
469 | cmp.le p10,p0 = 5,r30 |
---|
470 | ;; |
---|
471 | EX(.ex_handler_short, (p7) ld1 t2=[src1],2) |
---|
472 | EK(.ex_handler_short, (p8) ld1 t3=[src0],2) |
---|
473 | cmp.le p11,p0 = 6,r30 |
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474 | EX(.ex_handler_short, (p6) st1 [dst0] = t1,2) |
---|
475 | cmp.le p12,p0 = 7,r30 |
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476 | ;; |
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477 | EX(.ex_handler_short, (p9) ld1 t4=[src1],2) |
---|
478 | EK(.ex_handler_short, (p10) ld1 t5=[src0],2) |
---|
479 | EX(.ex_handler_short, (p7) st1 [dst1] = t2,2) |
---|
480 | EK(.ex_handler_short, (p8) st1 [dst0] = t3,2) |
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481 | ;; |
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482 | EX(.ex_handler_short, (p11) ld1 t6=[src1],2) |
---|
483 | EK(.ex_handler_short, (p12) ld1 t7=[src0],2) |
---|
484 | cmp.eq p6,p7=r28,r29 |
---|
485 | EX(.ex_handler_short, (p9) st1 [dst1] = t4,2) |
---|
486 | EK(.ex_handler_short, (p10) st1 [dst0] = t5,2) |
---|
487 | sub in2=in2,r30 |
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488 | ;; |
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489 | EX(.ex_handler_short, (p11) st1 [dst1] = t6,2) |
---|
490 | EK(.ex_handler_short, (p12) st1 [dst0] = t7) |
---|
491 | add dst0=in0,r30 // setup arguments |
---|
492 | add src0=in1,r30 |
---|
493 | (p6) br.cond.dptk .aligned_src |
---|
494 | (p7) br.cond.dpnt .unaligned_src |
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495 | ;; |
---|
496 | |
---|
497 | /* main loop body in jump table format */ |
---|
498 | #define COPYU(shift) \ |
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499 | 1: \ |
---|
500 | EX(.ex_handler, (p16) ld8 r32=[src0],8); /* 1 */ \ |
---|
501 | EK(.ex_handler, (p16) ld8 r36=[src1],8); \ |
---|
502 | (p17) shrp r35=r33,r34,shift;; /* 1 */ \ |
---|
503 | EX(.ex_handler, (p6) ld8 r22=[src1]); /* common, prime for tail section */ \ |
---|
504 | nop.m 0; \ |
---|
505 | (p16) shrp r38=r36,r37,shift; \ |
---|
506 | EX(.ex_handler, (p17) st8 [dst0]=r35,8); /* 1 */ \ |
---|
507 | EK(.ex_handler, (p17) st8 [dst1]=r39,8); \ |
---|
508 | br.ctop.dptk.few 1b;; \ |
---|
509 | (p7) add src1=-8,src1; /* back out for <8 byte case */ \ |
---|
510 | shrp r21=r22,r38,shift; /* speculative work */ \ |
---|
511 | br.sptk.few .unaligned_src_tail /* branch out of jump table */ \ |
---|
512 | ;; |
---|
513 | TEXT_ALIGN(32) |
---|
514 | .jump_table: |
---|
515 | COPYU(8) // unaligned cases |
---|
516 | .jmp1: |
---|
517 | COPYU(16) |
---|
518 | COPYU(24) |
---|
519 | COPYU(32) |
---|
520 | COPYU(40) |
---|
521 | COPYU(48) |
---|
522 | COPYU(56) |
---|
523 | |
---|
524 | #undef A |
---|
525 | #undef B |
---|
526 | #undef C |
---|
527 | #undef D |
---|
528 | |
---|
529 | /* |
---|
530 | * Due to lack of local tag support in gcc 2.x assembler, it is not clear which |
---|
531 | * instruction failed in the bundle. The exception algorithm is that we |
---|
532 | * first figure out the faulting address, then detect if there is any |
---|
533 | * progress made on the copy, if so, redo the copy from last known copied |
---|
534 | * location up to the faulting address (exclusive). In the copy_from_user |
---|
535 | * case, remaining byte in kernel buffer will be zeroed. |
---|
536 | * |
---|
537 | * Take copy_from_user as an example, in the code there are multiple loads |
---|
538 | * in a bundle and those multiple loads could span over two pages, the |
---|
539 | * faulting address is calculated as page_round_down(max(src0, src1)). |
---|
540 | * This is based on knowledge that if we can access one byte in a page, we |
---|
541 | * can access any byte in that page. |
---|
542 | * |
---|
543 | * predicate used in the exception handler: |
---|
544 | * p6-p7: direction |
---|
545 | * p10-p11: src faulting addr calculation |
---|
546 | * p12-p13: dst faulting addr calculation |
---|
547 | */ |
---|
548 | |
---|
549 | #define A r19 |
---|
550 | #define B r20 |
---|
551 | #define C r21 |
---|
552 | #define D r22 |
---|
553 | #define F r28 |
---|
554 | |
---|
555 | #define memset_arg0 r32 |
---|
556 | #define memset_arg2 r33 |
---|
557 | |
---|
558 | #define saved_retval loc0 |
---|
559 | #define saved_rtlink loc1 |
---|
560 | #define saved_pfs_stack loc2 |
---|
561 | |
---|
562 | .ex_hndlr_s: |
---|
563 | add src0=8,src0 |
---|
564 | br.sptk .ex_handler |
---|
565 | ;; |
---|
566 | .ex_hndlr_d: |
---|
567 | add dst0=8,dst0 |
---|
568 | br.sptk .ex_handler |
---|
569 | ;; |
---|
570 | .ex_hndlr_lcpy_1: |
---|
571 | mov src1=src_pre_mem |
---|
572 | mov dst1=dst_pre_mem |
---|
573 | cmp.gtu p10,p11=src_pre_mem,saved_in1 |
---|
574 | cmp.gtu p12,p13=dst_pre_mem,saved_in0 |
---|
575 | ;; |
---|
576 | (p10) add src0=8,saved_in1 |
---|
577 | (p11) mov src0=saved_in1 |
---|
578 | (p12) add dst0=8,saved_in0 |
---|
579 | (p13) mov dst0=saved_in0 |
---|
580 | br.sptk .ex_handler |
---|
581 | .ex_handler_lcpy: |
---|
582 | // in line_copy block, the preload addresses should always ahead |
---|
583 | // of the other two src/dst pointers. Furthermore, src1/dst1 should |
---|
584 | // always ahead of src0/dst0. |
---|
585 | mov src1=src_pre_mem |
---|
586 | mov dst1=dst_pre_mem |
---|
587 | .ex_handler: |
---|
588 | mov pr=saved_pr,-1 // first restore pr, lc, and pfs |
---|
589 | mov ar.lc=saved_lc |
---|
590 | mov ar.pfs=saved_pfs |
---|
591 | ;; |
---|
592 | .ex_handler_short: // fault occurred in these sections didn't change pr, lc, pfs |
---|
593 | cmp.ltu p6,p7=saved_in0, saved_in1 // get the copy direction |
---|
594 | cmp.ltu p10,p11=src0,src1 |
---|
595 | cmp.ltu p12,p13=dst0,dst1 |
---|
596 | fcmp.eq p8,p0=f6,f0 // is it memcpy? |
---|
597 | mov tmp = dst0 |
---|
598 | ;; |
---|
599 | (p11) mov src1 = src0 // pick the larger of the two |
---|
600 | (p13) mov dst0 = dst1 // make dst0 the smaller one |
---|
601 | (p13) mov dst1 = tmp // and dst1 the larger one |
---|
602 | ;; |
---|
603 | (p6) dep F = r0,dst1,0,PAGE_SHIFT // usr dst round down to page boundary |
---|
604 | (p7) dep F = r0,src1,0,PAGE_SHIFT // usr src round down to page boundary |
---|
605 | ;; |
---|
606 | (p6) cmp.le p14,p0=dst0,saved_in0 // no progress has been made on store |
---|
607 | (p7) cmp.le p14,p0=src0,saved_in1 // no progress has been made on load |
---|
608 | mov retval=saved_in2 |
---|
609 | (p8) ld1 tmp=[src1] // force an oops for memcpy call |
---|
610 | (p8) st1 [dst1]=r0 // force an oops for memcpy call |
---|
611 | (p14) br.ret.sptk.many rp |
---|
612 | |
---|
613 | /* |
---|
614 | * The remaining byte to copy is calculated as: |
---|
615 | * |
---|
616 | * A = (faulting_addr - orig_src) -> len to faulting ld address |
---|
617 | * or |
---|
618 | * (faulting_addr - orig_dst) -> len to faulting st address |
---|
619 | * B = (cur_dst - orig_dst) -> len copied so far |
---|
620 | * C = A - B -> len need to be copied |
---|
621 | * D = orig_len - A -> len need to be zeroed |
---|
622 | */ |
---|
623 | (p6) sub A = F, saved_in0 |
---|
624 | (p7) sub A = F, saved_in1 |
---|
625 | clrrrb |
---|
626 | ;; |
---|
627 | alloc saved_pfs_stack=ar.pfs,3,3,3,0 |
---|
628 | sub B = dst0, saved_in0 // how many byte copied so far |
---|
629 | ;; |
---|
630 | sub C = A, B |
---|
631 | sub D = saved_in2, A |
---|
632 | ;; |
---|
633 | cmp.gt p8,p0=C,r0 // more than 1 byte? |
---|
634 | add memset_arg0=saved_in0, A |
---|
635 | (p6) mov memset_arg2=0 // copy_to_user should not call memset |
---|
636 | (p7) mov memset_arg2=D // copy_from_user need to have kbuf zeroed |
---|
637 | mov r8=0 |
---|
638 | mov saved_retval = D |
---|
639 | mov saved_rtlink = b0 |
---|
640 | |
---|
641 | add out0=saved_in0, B |
---|
642 | add out1=saved_in1, B |
---|
643 | mov out2=C |
---|
644 | (p8) br.call.sptk.few b0=__copy_user // recursive call |
---|
645 | ;; |
---|
646 | |
---|
647 | add saved_retval=saved_retval,r8 // above might return non-zero value |
---|
648 | cmp.gt p8,p0=memset_arg2,r0 // more than 1 byte? |
---|
649 | mov out0=memset_arg0 // *s |
---|
650 | mov out1=r0 // c |
---|
651 | mov out2=memset_arg2 // n |
---|
652 | (p8) br.call.sptk.few b0=memset |
---|
653 | ;; |
---|
654 | |
---|
655 | mov retval=saved_retval |
---|
656 | mov ar.pfs=saved_pfs_stack |
---|
657 | mov b0=saved_rtlink |
---|
658 | br.ret.sptk.many rp |
---|
659 | |
---|
660 | /* end of McKinley specific optimization */ |
---|
661 | END(__copy_user) |
---|