| 1 | /* |
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| 2 | * Copyright (C) 2000 Hewlett-Packard Co |
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| 3 | * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com> |
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| 4 | * |
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| 5 | * 32-bit integer division. |
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| 6 | * |
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| 7 | * This code is based on the application note entitled "Divide, Square Root |
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| 8 | * and Remainder Algorithms for the IA-64 Architecture". This document |
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| 9 | * is available as Intel document number 248725-002 or via the web at |
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| 10 | * http://developer.intel.com/software/opensource/numerics/ |
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| 11 | * |
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| 12 | * For more details on the theory behind these algorithms, see "IA-64 |
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| 13 | * and Elementary Functions" by Peter Markstein; HP Professional Books |
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| 14 | * (http://www.hp.com/go/retailbooks/) |
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| 15 | */ |
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| 16 | |
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| 17 | #include <asm/asmmacro.h> |
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| 18 | |
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| 19 | #ifdef MODULO |
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| 20 | # define OP mod |
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| 21 | #else |
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| 22 | # define OP div |
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| 23 | #endif |
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| 24 | |
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| 25 | #ifdef UNSIGNED |
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| 26 | # define SGN u |
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| 27 | # define EXTEND zxt4 |
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| 28 | # define INT_TO_FP(a,b) fcvt.xuf.s1 a=b |
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| 29 | # define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b |
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| 30 | #else |
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| 31 | # define SGN |
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| 32 | # define EXTEND sxt4 |
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| 33 | # define INT_TO_FP(a,b) fcvt.xf a=b |
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| 34 | # define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b |
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| 35 | #endif |
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| 36 | |
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| 37 | #define PASTE1(a,b) a##b |
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| 38 | #define PASTE(a,b) PASTE1(a,b) |
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| 39 | #define NAME PASTE(PASTE(__,SGN),PASTE(OP,si3)) |
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| 40 | |
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| 41 | GLOBAL_ENTRY(NAME) |
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| 42 | .regstk 2,0,0,0 |
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| 43 | // Transfer inputs to FP registers. |
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| 44 | mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) |
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| 45 | EXTEND in0 = in0 // in0 = a |
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| 46 | EXTEND in1 = in1 // in1 = b |
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| 47 | ;; |
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| 48 | setf.sig f8 = in0 |
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| 49 | setf.sig f9 = in1 |
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| 50 | #ifdef MODULO |
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| 51 | sub in1 = r0, in1 // in1 = -b |
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| 52 | #endif |
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| 53 | ;; |
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| 54 | // Convert the inputs to FP, to avoid FP software-assist faults. |
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| 55 | INT_TO_FP(f8, f8) |
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| 56 | INT_TO_FP(f9, f9) |
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| 57 | ;; |
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| 58 | setf.exp f7 = r2 // f7 = 2^-34 |
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| 59 | frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) |
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| 60 | ;; |
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| 61 | (p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 |
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| 62 | (p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 |
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| 63 | ;; |
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| 64 | #ifdef MODULO |
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| 65 | setf.sig f9 = in1 // f9 = -b |
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| 66 | #endif |
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| 67 | (p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 |
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| 68 | (p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 |
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| 69 | ;; |
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| 70 | #ifdef MODULO |
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| 71 | setf.sig f7 = in0 |
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| 72 | #endif |
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| 73 | (p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 |
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| 74 | ;; |
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| 75 | FP_TO_INT(f6, f6) // q = trunc(q2) |
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| 76 | ;; |
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| 77 | #ifdef MODULO |
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| 78 | xma.l f6 = f6, f9, f7 // r = q*(-b) + a |
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| 79 | ;; |
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| 80 | #endif |
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| 81 | getf.sig r8 = f6 // transfer result to result register |
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| 82 | br.ret.sptk.many rp |
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| 83 | END(NAME) |
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