/* 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; }