362 lines
8.4 KiB
C
362 lines
8.4 KiB
C
|
// SPDX-License-Identifier: GPL-2.0-or-later
|
||
|
|
/*
|
||
|
|
NetWinder Floating Point Emulator
|
||
|
|
(c) Rebel.COM, 1998,1999
|
||
|
|
(c) Philip Blundell, 1999, 2001
|
||
|
|
|
||
|
|
Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
|
||
|
|
|
||
|
|
*/
|
||
|
|
|
||
|
|
#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;
|
||
|
|
}
|