diff options
Diffstat (limited to 'kernel/arch/arm/nwfpe/fpa11_cprt.c')
| -rw-r--r-- | kernel/arch/arm/nwfpe/fpa11_cprt.c | 373 |
1 files changed, 373 insertions, 0 deletions
diff --git a/kernel/arch/arm/nwfpe/fpa11_cprt.c b/kernel/arch/arm/nwfpe/fpa11_cprt.c new file mode 100644 index 000000000..31c4eeec1 --- /dev/null +++ b/kernel/arch/arm/nwfpe/fpa11_cprt.c @@ -0,0 +1,373 @@ +/* + NetWinder Floating Point Emulator + (c) Rebel.COM, 1998,1999 + (c) Philip Blundell, 1999, 2001 + + Direct questions, comments to Scott Bambrough <scottb@netwinder.org> + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 2 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. +*/ + +#include "fpa11.h" +#include "fpopcode.h" +#include "fpa11.inl" +#include "fpmodule.h" +#include "fpmodule.inl" +#include "softfloat.h" + +unsigned int PerformFLT(const unsigned int opcode); +unsigned int PerformFIX(const unsigned int opcode); + +static unsigned int PerformComparison(const unsigned int opcode); + +unsigned int EmulateCPRT(const unsigned int opcode) +{ + + if (opcode & 0x800000) { + /* This is some variant of a comparison (PerformComparison + will sort out which one). Since most of the other CPRT + instructions are oddball cases of some sort or other it + makes sense to pull this out into a fast path. */ + return PerformComparison(opcode); + } + + /* Hint to GCC that we'd like a jump table rather than a load of CMPs */ + switch ((opcode & 0x700000) >> 20) { + case FLT_CODE >> 20: + return PerformFLT(opcode); + break; + case FIX_CODE >> 20: + return PerformFIX(opcode); + break; + + case WFS_CODE >> 20: + writeFPSR(readRegister(getRd(opcode))); + break; + case RFS_CODE >> 20: + writeRegister(getRd(opcode), readFPSR()); + break; + + default: + return 0; + } + + return 1; +} + +unsigned int PerformFLT(const unsigned int opcode) +{ + FPA11 *fpa11 = GET_FPA11(); + struct roundingData roundData; + + roundData.mode = SetRoundingMode(opcode); + roundData.precision = SetRoundingPrecision(opcode); + roundData.exception = 0; + + switch (opcode & MASK_ROUNDING_PRECISION) { + case ROUND_SINGLE: + { + fpa11->fType[getFn(opcode)] = typeSingle; + fpa11->fpreg[getFn(opcode)].fSingle = int32_to_float32(&roundData, readRegister(getRd(opcode))); + } + break; + + case ROUND_DOUBLE: + { + fpa11->fType[getFn(opcode)] = typeDouble; + fpa11->fpreg[getFn(opcode)].fDouble = int32_to_float64(readRegister(getRd(opcode))); + } + break; + +#ifdef CONFIG_FPE_NWFPE_XP + case ROUND_EXTENDED: + { + fpa11->fType[getFn(opcode)] = typeExtended; + fpa11->fpreg[getFn(opcode)].fExtended = int32_to_floatx80(readRegister(getRd(opcode))); + } + break; +#endif + + default: + return 0; + } + + if (roundData.exception) + float_raise(roundData.exception); + + return 1; +} + +unsigned int PerformFIX(const unsigned int opcode) +{ + FPA11 *fpa11 = GET_FPA11(); + unsigned int Fn = getFm(opcode); + struct roundingData roundData; + + roundData.mode = SetRoundingMode(opcode); + roundData.precision = SetRoundingPrecision(opcode); + roundData.exception = 0; + + switch (fpa11->fType[Fn]) { + case typeSingle: + { + writeRegister(getRd(opcode), float32_to_int32(&roundData, fpa11->fpreg[Fn].fSingle)); + } + break; + + case typeDouble: + { + writeRegister(getRd(opcode), float64_to_int32(&roundData, fpa11->fpreg[Fn].fDouble)); + } + break; + +#ifdef CONFIG_FPE_NWFPE_XP + case typeExtended: + { + writeRegister(getRd(opcode), floatx80_to_int32(&roundData, fpa11->fpreg[Fn].fExtended)); + } + break; +#endif + + default: + return 0; + } + + if (roundData.exception) + float_raise(roundData.exception); + + return 1; +} + +/* This instruction sets the flags N, Z, C, V in the FPSR. */ +static unsigned int PerformComparison(const unsigned int opcode) +{ + FPA11 *fpa11 = GET_FPA11(); + unsigned int Fn = getFn(opcode), Fm = getFm(opcode); + int e_flag = opcode & 0x400000; /* 1 if CxFE */ + int n_flag = opcode & 0x200000; /* 1 if CNxx */ + unsigned int flags = 0; + +#ifdef CONFIG_FPE_NWFPE_XP + floatx80 rFn, rFm; + + /* Check for unordered condition and convert all operands to 80-bit + format. + ?? Might be some mileage in avoiding this conversion if possible. + Eg, if both operands are 32-bit, detect this and do a 32-bit + comparison (cheaper than an 80-bit one). */ + switch (fpa11->fType[Fn]) { + case typeSingle: + //printk("single.\n"); + if (float32_is_nan(fpa11->fpreg[Fn].fSingle)) + goto unordered; + rFn = float32_to_floatx80(fpa11->fpreg[Fn].fSingle); + break; + + case typeDouble: + //printk("double.\n"); + if (float64_is_nan(fpa11->fpreg[Fn].fDouble)) + goto unordered; + rFn = float64_to_floatx80(fpa11->fpreg[Fn].fDouble); + break; + + case typeExtended: + //printk("extended.\n"); + if (floatx80_is_nan(fpa11->fpreg[Fn].fExtended)) + goto unordered; + rFn = fpa11->fpreg[Fn].fExtended; + break; + + default: + return 0; + } + + if (CONSTANT_FM(opcode)) { + //printk("Fm is a constant: #%d.\n",Fm); + rFm = getExtendedConstant(Fm); + if (floatx80_is_nan(rFm)) + goto unordered; + } else { + //printk("Fm = r%d which contains a ",Fm); + switch (fpa11->fType[Fm]) { + case typeSingle: + //printk("single.\n"); + if (float32_is_nan(fpa11->fpreg[Fm].fSingle)) + goto unordered; + rFm = float32_to_floatx80(fpa11->fpreg[Fm].fSingle); + break; + + case typeDouble: + //printk("double.\n"); + if (float64_is_nan(fpa11->fpreg[Fm].fDouble)) + goto unordered; + rFm = float64_to_floatx80(fpa11->fpreg[Fm].fDouble); + break; + + case typeExtended: + //printk("extended.\n"); + if (floatx80_is_nan(fpa11->fpreg[Fm].fExtended)) + goto unordered; + rFm = fpa11->fpreg[Fm].fExtended; + break; + + default: + return 0; + } + } + + if (n_flag) + rFm.high ^= 0x8000; + + /* test for less than condition */ + if (floatx80_lt(rFn, rFm)) + flags |= CC_NEGATIVE; + + /* test for equal condition */ + if (floatx80_eq(rFn, rFm)) + flags |= CC_ZERO; + + /* test for greater than or equal condition */ + if (floatx80_lt(rFm, rFn)) + flags |= CC_CARRY; + +#else + if (CONSTANT_FM(opcode)) { + /* Fm is a constant. Do the comparison in whatever precision + Fn happens to be stored in. */ + if (fpa11->fType[Fn] == typeSingle) { + float32 rFm = getSingleConstant(Fm); + float32 rFn = fpa11->fpreg[Fn].fSingle; + + if (float32_is_nan(rFn)) + goto unordered; + + if (n_flag) + rFm ^= 0x80000000; + + /* test for less than condition */ + if (float32_lt_nocheck(rFn, rFm)) + flags |= CC_NEGATIVE; + + /* test for equal condition */ + if (float32_eq_nocheck(rFn, rFm)) + flags |= CC_ZERO; + + /* test for greater than or equal condition */ + if (float32_lt_nocheck(rFm, rFn)) + flags |= CC_CARRY; + } else { + float64 rFm = getDoubleConstant(Fm); + float64 rFn = fpa11->fpreg[Fn].fDouble; + + if (float64_is_nan(rFn)) + goto unordered; + + if (n_flag) + rFm ^= 0x8000000000000000ULL; + + /* test for less than condition */ + if (float64_lt_nocheck(rFn, rFm)) + flags |= CC_NEGATIVE; + + /* test for equal condition */ + if (float64_eq_nocheck(rFn, rFm)) + flags |= CC_ZERO; + + /* test for greater than or equal condition */ + if (float64_lt_nocheck(rFm, rFn)) + flags |= CC_CARRY; + } + } else { + /* Both operands are in registers. */ + if (fpa11->fType[Fn] == typeSingle + && fpa11->fType[Fm] == typeSingle) { + float32 rFm = fpa11->fpreg[Fm].fSingle; + float32 rFn = fpa11->fpreg[Fn].fSingle; + + if (float32_is_nan(rFn) + || float32_is_nan(rFm)) + goto unordered; + + if (n_flag) + rFm ^= 0x80000000; + + /* test for less than condition */ + if (float32_lt_nocheck(rFn, rFm)) + flags |= CC_NEGATIVE; + + /* test for equal condition */ + if (float32_eq_nocheck(rFn, rFm)) + flags |= CC_ZERO; + + /* test for greater than or equal condition */ + if (float32_lt_nocheck(rFm, rFn)) + flags |= CC_CARRY; + } else { + /* Promote 32-bit operand to 64 bits. */ + float64 rFm, rFn; + + rFm = (fpa11->fType[Fm] == typeSingle) ? + float32_to_float64(fpa11->fpreg[Fm].fSingle) + : fpa11->fpreg[Fm].fDouble; + + rFn = (fpa11->fType[Fn] == typeSingle) ? + float32_to_float64(fpa11->fpreg[Fn].fSingle) + : fpa11->fpreg[Fn].fDouble; + + if (float64_is_nan(rFn) + || float64_is_nan(rFm)) + goto unordered; + + if (n_flag) + rFm ^= 0x8000000000000000ULL; + + /* test for less than condition */ + if (float64_lt_nocheck(rFn, rFm)) + flags |= CC_NEGATIVE; + + /* test for equal condition */ + if (float64_eq_nocheck(rFn, rFm)) + flags |= CC_ZERO; + + /* test for greater than or equal condition */ + if (float64_lt_nocheck(rFm, rFn)) + flags |= CC_CARRY; + } + } + +#endif + + writeConditionCodes(flags); + + return 1; + + unordered: + /* ?? The FPA data sheet is pretty vague about this, in particular + about whether the non-E comparisons can ever raise exceptions. + This implementation is based on a combination of what it says in + the data sheet, observation of how the Acorn emulator actually + behaves (and how programs expect it to) and guesswork. */ + flags |= CC_OVERFLOW; + flags &= ~(CC_ZERO | CC_NEGATIVE); + + if (BIT_AC & readFPSR()) + flags |= CC_CARRY; + + if (e_flag) + float_raise(float_flag_invalid); + + writeConditionCodes(flags); + return 1; +} |