forked from Minki/linux
f148af2593
Patch from Richard Purdie NWFPE used global variables which meant it wasn't safe for use with preemptive kernels. This patch removes them and communicates the information between functions in a preempt safe manner. Generation of some exceptions was broken and this has also been corrected. Tests with glibc's maths test suite show no change in the results before/after this patch. Signed-off-by: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
380 lines
9.2 KiB
C
380 lines
9.2 KiB
C
/*
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NetWinder Floating Point Emulator
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(c) Rebel.COM, 1998,1999
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(c) Philip Blundell, 1999, 2001
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Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/config.h>
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#include "fpa11.h"
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#include "fpopcode.h"
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#include "fpa11.inl"
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#include "fpmodule.h"
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#include "fpmodule.inl"
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#ifdef CONFIG_FPE_NWFPE_XP
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extern flag floatx80_is_nan(floatx80);
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#endif
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extern flag float64_is_nan(float64);
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extern flag float32_is_nan(float32);
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unsigned int PerformFLT(const unsigned int opcode);
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unsigned int PerformFIX(const unsigned int opcode);
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static unsigned int PerformComparison(const unsigned int opcode);
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unsigned int EmulateCPRT(const unsigned int opcode)
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{
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if (opcode & 0x800000) {
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/* This is some variant of a comparison (PerformComparison
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will sort out which one). Since most of the other CPRT
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instructions are oddball cases of some sort or other it
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makes sense to pull this out into a fast path. */
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return PerformComparison(opcode);
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}
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/* Hint to GCC that we'd like a jump table rather than a load of CMPs */
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switch ((opcode & 0x700000) >> 20) {
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case FLT_CODE >> 20:
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return PerformFLT(opcode);
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break;
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case FIX_CODE >> 20:
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return PerformFIX(opcode);
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break;
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case WFS_CODE >> 20:
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writeFPSR(readRegister(getRd(opcode)));
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break;
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case RFS_CODE >> 20:
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writeRegister(getRd(opcode), readFPSR());
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break;
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default:
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return 0;
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}
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return 1;
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}
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unsigned int PerformFLT(const unsigned int opcode)
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{
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FPA11 *fpa11 = GET_FPA11();
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struct roundingData roundData;
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roundData.mode = SetRoundingMode(opcode);
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roundData.precision = SetRoundingPrecision(opcode);
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roundData.exception = 0;
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switch (opcode & MASK_ROUNDING_PRECISION) {
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case ROUND_SINGLE:
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{
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fpa11->fType[getFn(opcode)] = typeSingle;
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fpa11->fpreg[getFn(opcode)].fSingle = int32_to_float32(&roundData, readRegister(getRd(opcode)));
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}
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break;
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case ROUND_DOUBLE:
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{
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fpa11->fType[getFn(opcode)] = typeDouble;
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fpa11->fpreg[getFn(opcode)].fDouble = int32_to_float64(readRegister(getRd(opcode)));
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}
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break;
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#ifdef CONFIG_FPE_NWFPE_XP
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case ROUND_EXTENDED:
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{
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fpa11->fType[getFn(opcode)] = typeExtended;
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fpa11->fpreg[getFn(opcode)].fExtended = int32_to_floatx80(readRegister(getRd(opcode)));
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}
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break;
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#endif
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default:
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return 0;
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}
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if (roundData.exception)
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float_raise(roundData.exception);
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return 1;
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}
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unsigned int PerformFIX(const unsigned int opcode)
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{
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FPA11 *fpa11 = GET_FPA11();
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unsigned int Fn = getFm(opcode);
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struct roundingData roundData;
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roundData.mode = SetRoundingMode(opcode);
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roundData.precision = SetRoundingPrecision(opcode);
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roundData.exception = 0;
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switch (fpa11->fType[Fn]) {
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case typeSingle:
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{
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writeRegister(getRd(opcode), float32_to_int32(&roundData, fpa11->fpreg[Fn].fSingle));
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}
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break;
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case typeDouble:
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{
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writeRegister(getRd(opcode), float64_to_int32(&roundData, fpa11->fpreg[Fn].fDouble));
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}
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break;
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#ifdef CONFIG_FPE_NWFPE_XP
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case typeExtended:
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{
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writeRegister(getRd(opcode), floatx80_to_int32(&roundData, fpa11->fpreg[Fn].fExtended));
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}
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break;
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#endif
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default:
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return 0;
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}
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if (roundData.exception)
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float_raise(roundData.exception);
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return 1;
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}
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/* This instruction sets the flags N, Z, C, V in the FPSR. */
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static unsigned int PerformComparison(const unsigned int opcode)
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{
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FPA11 *fpa11 = GET_FPA11();
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unsigned int Fn = getFn(opcode), Fm = getFm(opcode);
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int e_flag = opcode & 0x400000; /* 1 if CxFE */
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int n_flag = opcode & 0x200000; /* 1 if CNxx */
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unsigned int flags = 0;
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#ifdef CONFIG_FPE_NWFPE_XP
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floatx80 rFn, rFm;
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/* Check for unordered condition and convert all operands to 80-bit
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format.
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?? Might be some mileage in avoiding this conversion if possible.
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Eg, if both operands are 32-bit, detect this and do a 32-bit
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comparison (cheaper than an 80-bit one). */
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switch (fpa11->fType[Fn]) {
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case typeSingle:
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//printk("single.\n");
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if (float32_is_nan(fpa11->fpreg[Fn].fSingle))
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goto unordered;
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rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle);
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break;
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case typeDouble:
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//printk("double.\n");
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if (float64_is_nan(fpa11->fpreg[Fn].fDouble))
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goto unordered;
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rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble);
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break;
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case typeExtended:
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//printk("extended.\n");
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if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended))
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goto unordered;
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rFn = fpa11->fpreg[Fn].fExtended;
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break;
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default:
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return 0;
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}
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if (CONSTANT_FM(opcode)) {
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//printk("Fm is a constant: #%d.\n",Fm);
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rFm = getExtendedConstant(Fm);
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if (floatx80_is_nan(rFm))
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goto unordered;
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} else {
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//printk("Fm = r%d which contains a ",Fm);
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switch (fpa11->fType[Fm]) {
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case typeSingle:
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//printk("single.\n");
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if (float32_is_nan(fpa11->fpreg[Fm].fSingle))
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goto unordered;
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rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle);
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break;
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case typeDouble:
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//printk("double.\n");
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if (float64_is_nan(fpa11->fpreg[Fm].fDouble))
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goto unordered;
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rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble);
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break;
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case typeExtended:
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//printk("extended.\n");
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if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended))
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goto unordered;
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rFm = fpa11->fpreg[Fm].fExtended;
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break;
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default:
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return 0;
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}
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}
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if (n_flag)
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rFm.high ^= 0x8000;
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/* test for less than condition */
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if (floatx80_lt(rFn, rFm))
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flags |= CC_NEGATIVE;
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/* test for equal condition */
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if (floatx80_eq(rFn, rFm))
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flags |= CC_ZERO;
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/* test for greater than or equal condition */
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if (floatx80_lt(rFm, rFn))
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flags |= CC_CARRY;
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#else
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if (CONSTANT_FM(opcode)) {
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/* Fm is a constant. Do the comparison in whatever precision
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Fn happens to be stored in. */
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if (fpa11->fType[Fn] == typeSingle) {
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float32 rFm = getSingleConstant(Fm);
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float32 rFn = fpa11->fpreg[Fn].fSingle;
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if (float32_is_nan(rFn))
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goto unordered;
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if (n_flag)
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rFm ^= 0x80000000;
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/* test for less than condition */
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if (float32_lt_nocheck(rFn, rFm))
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flags |= CC_NEGATIVE;
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/* test for equal condition */
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if (float32_eq_nocheck(rFn, rFm))
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flags |= CC_ZERO;
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/* test for greater than or equal condition */
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if (float32_lt_nocheck(rFm, rFn))
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flags |= CC_CARRY;
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} else {
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float64 rFm = getDoubleConstant(Fm);
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float64 rFn = fpa11->fpreg[Fn].fDouble;
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if (float64_is_nan(rFn))
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goto unordered;
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if (n_flag)
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rFm ^= 0x8000000000000000ULL;
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/* test for less than condition */
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if (float64_lt_nocheck(rFn, rFm))
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flags |= CC_NEGATIVE;
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/* test for equal condition */
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if (float64_eq_nocheck(rFn, rFm))
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flags |= CC_ZERO;
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/* test for greater than or equal condition */
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if (float64_lt_nocheck(rFm, rFn))
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flags |= CC_CARRY;
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}
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} else {
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/* Both operands are in registers. */
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if (fpa11->fType[Fn] == typeSingle
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&& fpa11->fType[Fm] == typeSingle) {
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float32 rFm = fpa11->fpreg[Fm].fSingle;
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float32 rFn = fpa11->fpreg[Fn].fSingle;
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if (float32_is_nan(rFn)
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|| float32_is_nan(rFm))
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goto unordered;
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if (n_flag)
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rFm ^= 0x80000000;
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/* test for less than condition */
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if (float32_lt_nocheck(rFn, rFm))
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flags |= CC_NEGATIVE;
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/* test for equal condition */
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if (float32_eq_nocheck(rFn, rFm))
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flags |= CC_ZERO;
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/* test for greater than or equal condition */
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if (float32_lt_nocheck(rFm, rFn))
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flags |= CC_CARRY;
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} else {
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/* Promote 32-bit operand to 64 bits. */
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float64 rFm, rFn;
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rFm = (fpa11->fType[Fm] == typeSingle) ?
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float32_to_float64(fpa11->fpreg[Fm].fSingle)
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: fpa11->fpreg[Fm].fDouble;
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rFn = (fpa11->fType[Fn] == typeSingle) ?
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float32_to_float64(fpa11->fpreg[Fn].fSingle)
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: fpa11->fpreg[Fn].fDouble;
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if (float64_is_nan(rFn)
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|| float64_is_nan(rFm))
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goto unordered;
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if (n_flag)
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rFm ^= 0x8000000000000000ULL;
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/* test for less than condition */
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if (float64_lt_nocheck(rFn, rFm))
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flags |= CC_NEGATIVE;
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/* test for equal condition */
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if (float64_eq_nocheck(rFn, rFm))
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flags |= CC_ZERO;
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/* test for greater than or equal condition */
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if (float64_lt_nocheck(rFm, rFn))
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flags |= CC_CARRY;
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}
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}
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#endif
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writeConditionCodes(flags);
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return 1;
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unordered:
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/* ?? The FPA data sheet is pretty vague about this, in particular
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about whether the non-E comparisons can ever raise exceptions.
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This implementation is based on a combination of what it says in
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the data sheet, observation of how the Acorn emulator actually
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behaves (and how programs expect it to) and guesswork. */
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flags |= CC_OVERFLOW;
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flags &= ~(CC_ZERO | CC_NEGATIVE);
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if (BIT_AC & readFPSR())
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flags |= CC_CARRY;
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if (e_flag)
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float_raise(float_flag_invalid);
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writeConditionCodes(flags);
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return 1;
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}
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