projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 1da177e4 LT |
1 | /* |
| 2 | * Copyright (C) 2000 Hewlett-Packard Co | |
| 3 | * Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com> | |
| 4 | * | |
| 5 | * 32-bit integer division. | |
| 6 | * | |
| 7 | * This code is based on the application note entitled "Divide, Square Root | |
| 8 | * and Remainder Algorithms for the IA-64 Architecture". This document | |
| 9 | * is available as Intel document number 248725-002 or via the web at | |
| 10 | * http://developer.intel.com/software/opensource/numerics/ | |
| 11 | * | |
| 12 | * For more details on the theory behind these algorithms, see "IA-64 | |
| 13 | * and Elementary Functions" by Peter Markstein; HP Professional Books | |
| a9eb221a | 14 | * (http://www.goodreads.com/book/show/2019887.Ia_64_and_Elementary_Functions) |
| 1da177e4 LT |
15 | */ |
| 16 | ||
| 17 | #include <asm/asmmacro.h> | |
| e007c533 | 18 | #include <asm/export.h> |
| 1da177e4 LT |
19 | |
| 20 | #ifdef MODULO | |
| 21 | # define OP mod | |
| 22 | #else | |
| 23 | # define OP div | |
| 24 | #endif | |
| 25 | ||
| 26 | #ifdef UNSIGNED | |
| 27 | # define SGN u | |
| 28 | # define EXTEND zxt4 | |
| 29 | # define INT_TO_FP(a,b) fcvt.xuf.s1 a=b | |
| 30 | # define FP_TO_INT(a,b) fcvt.fxu.trunc.s1 a=b | |
| 31 | #else | |
| 32 | # define SGN | |
| 33 | # define EXTEND sxt4 | |
| 34 | # define INT_TO_FP(a,b) fcvt.xf a=b | |
| 35 | # define FP_TO_INT(a,b) fcvt.fx.trunc.s1 a=b | |
| 36 | #endif | |
| 37 | ||
| 38 | #define PASTE1(a,b) a##b | |
| 39 | #define PASTE(a,b) PASTE1(a,b) | |
| 40 | #define NAME PASTE(PASTE(__,SGN),PASTE(OP,si3)) | |
| 41 | ||
| 42 | GLOBAL_ENTRY(NAME) | |
| 43 | .regstk 2,0,0,0 | |
| 44 | // Transfer inputs to FP registers. | |
| 45 | mov r2 = 0xffdd // r2 = -34 + 65535 (fp reg format bias) | |
| 46 | EXTEND in0 = in0 // in0 = a | |
| 47 | EXTEND in1 = in1 // in1 = b | |
| 48 | ;; | |
| 49 | setf.sig f8 = in0 | |
| 50 | setf.sig f9 = in1 | |
| 51 | #ifdef MODULO | |
| 52 | sub in1 = r0, in1 // in1 = -b | |
| 53 | #endif | |
| 54 | ;; | |
| 55 | // Convert the inputs to FP, to avoid FP software-assist faults. | |
| 56 | INT_TO_FP(f8, f8) | |
| 57 | INT_TO_FP(f9, f9) | |
| 58 | ;; | |
| 59 | setf.exp f7 = r2 // f7 = 2^-34 | |
| 60 | frcpa.s1 f6, p6 = f8, f9 // y0 = frcpa(b) | |
| 61 | ;; | |
| 62 | (p6) fmpy.s1 f8 = f8, f6 // q0 = a*y0 | |
| 63 | (p6) fnma.s1 f6 = f9, f6, f1 // e0 = -b*y0 + 1 | |
| 64 | ;; | |
| 65 | #ifdef MODULO | |
| 66 | setf.sig f9 = in1 // f9 = -b | |
| 67 | #endif | |
| 68 | (p6) fma.s1 f8 = f6, f8, f8 // q1 = e0*q0 + q0 | |
| 69 | (p6) fma.s1 f6 = f6, f6, f7 // e1 = e0*e0 + 2^-34 | |
| 70 | ;; | |
| 71 | #ifdef MODULO | |
| 72 | setf.sig f7 = in0 | |
| 73 | #endif | |
| 74 | (p6) fma.s1 f6 = f6, f8, f8 // q2 = e1*q1 + q1 | |
| 75 | ;; | |
| 76 | FP_TO_INT(f6, f6) // q = trunc(q2) | |
| 77 | ;; | |
| 78 | #ifdef MODULO | |
| 79 | xma.l f6 = f6, f9, f7 // r = q*(-b) + a | |
| 80 | ;; | |
| 81 | #endif | |
| 82 | getf.sig r8 = f6 // transfer result to result register | |
| 83 | br.ret.sptk.many rp | |
| 84 | END(NAME) | |
| e007c533 | 85 | EXPORT_SYMBOL(NAME) |