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;
}
void float_raise(signed char flags)
{
register unsigned int fpsr, cumulativeTraps;
#ifdef CONFIG_DEBUG_USER
printk(KERN_DEBUG
"NWFPE: %s[%d] takes exception %08x at %p from %08lx\n",
current->comm, current->pid, flags,
__builtin_return_address(0), GET_USERREG()[15]);
#endif
/* Keep SoftFloat exception flags up to date. */
float_exception_flags |= flags;
/* Read fpsr and initialize the cumulativeTraps. */
fpsr = readFPSR();
cumulativeTraps = 0;
/* For each type of exception, the cumulative trap exception bit is only
set if the corresponding trap enable bit is not set. */
if ((!(fpsr & BIT_IXE)) && (flags & BIT_IXC))
cumulativeTraps |= BIT_IXC;
if ((!(fpsr & BIT_UFE)) && (flags & BIT_UFC))
cumulativeTraps |= BIT_UFC;
if ((!(fpsr & BIT_OFE)) && (flags & BIT_OFC))
cumulativeTraps |= BIT_OFC;
if ((!(fpsr & BIT_DZE)) && (flags & BIT_DZC))
cumulativeTraps |= BIT_DZC;
if ((!(fpsr & BIT_IOE)) && (flags & BIT_IOC))
cumulativeTraps |= BIT_IOC;
/* Set the cumulative exceptions flags. */
if (cumulativeTraps)
writeFPSR(fpsr | cumulativeTraps);
/* Raise an exception if necessary. */
if (fpsr & (flags << 16))
fp_send_sig(SIGFPE, current, 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;
}
