Both x87 and m68k need the low parts of the quotient for their
remainder operations. Arrange for floatx80_modrem to track those bits
and return them via a pointer.
The architectures using float32_rem and float64_rem do not appear to
need this information, so the *_rem interface is left unchanged and
the information returned only from floatx80_modrem. The logic used to
determine the low 7 bits of the quotient for m68k
(target/m68k/fpu_helper.c:make_quotient) appears completely bogus (it
looks at the result of converting the remainder to integer, the
quotient having been discarded by that point); this patch does not
change that, but the m68k maintainers may wish to do so.
Signed-off-by: Joseph Myers
---
fpu/softfloat.c | 23 ++-
include/fpu/softfloat.h | 3 ++-
2 files changed, 20 insertions(+), 6 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index 423a815196..c3c3f382af 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -5684,10 +5684,11 @@ floatx80 floatx80_div(floatx80 a, floatx80 b,
float_status *status)
| `a' with respect to the corresponding value `b'. The operation is performed
| according to the IEC/IEEE Standard for Binary Floating-Point Arithmetic,
| if 'mod' is false; if 'mod' is true, return the remainder based on truncating
-| the quotient toward zero instead.
+| the quotient toward zero instead. '*quotient' is set to the low 64 bits of
+| the absolute value of the integer quotient.
**/
-floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
+floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod, uint64_t *quotient,
float_status *status)
{
bool aSign, zSign;
@@ -5695,6 +5696,7 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
uint64_t aSig0, aSig1, bSig;
uint64_t q, term0, term1, alternateASig0, alternateASig1;
+*quotient = 0;
if (floatx80_invalid_encoding(a) || floatx80_invalid_encoding(b)) {
float_raise(float_flag_invalid, status);
return floatx80_default_nan(status);
@@ -5749,7 +5751,7 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
shift128Right( aSig0, 0, 1, , );
expDiff = 0;
}
-q = ( bSig <= aSig0 );
+*quotient = q = ( bSig <= aSig0 );
if ( q ) aSig0 -= bSig;
expDiff -= 64;
while ( 0 < expDiff ) {
@@ -5759,6 +5761,8 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
sub128( aSig0, aSig1, term0, term1, , );
shortShift128Left( aSig0, aSig1, 62, , );
expDiff -= 62;
+*quotient <<= 62;
+*quotient += q;
}
expDiff += 64;
if ( 0 < expDiff ) {
@@ -5772,6 +5776,12 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool
mod,
++q;
sub128( aSig0, aSig1, term0, term1, , );
}
+if (expDiff < 64) {
+*quotient <<= expDiff;
+} else {
+*quotient = 0;
+}
+*quotient += q;
}
else {
term1 = 0;
@@ -5786,6 +5796,7 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
aSig0 = alternateASig0;
aSig1 = alternateASig1;
zSign = ! zSign;
+++*quotient;
}
}
return
@@ -5802,7 +5813,8 @@ floatx80 floatx80_modrem(floatx80 a, floatx80 b, bool mod,
floatx80 floatx80_rem(floatx80 a, floatx80 b, float_status *status)
{
-return floatx80_modrem(a, b, false, status);
+uint64_t quotient;
+return floatx80_modrem(a, b, false, , status);
}
/*
@@ -5813,7 +5825,8 @@ floatx80 floatx80_rem(floatx80 a, floatx80 b,
float_status *status)
floatx80 floatx80_mod(floatx80 a, floatx80 b, float_status *status)
{
-return floatx80_modrem(a, b, true, status);
+uint64_t quotient;
+return floatx80_modrem(a, b, true, , status);
}
/*
diff --git a/include/fpu/softfloat.h b/include/fpu/softfloat.h
index bff6934d09..ff4e2605b1 100644
--- a/include/fpu/softfloat.h
+++ b/include/fpu/softfloat.h
@@ -687,7 +687,8 @@ floatx80 floatx80_add(floatx80, floatx80, float_status
*status);
floatx80 floatx80_sub(floatx80, floatx80, float_status *status);
floatx80 floatx80_mul(floatx80, floatx80, float_status *status);
floatx80 floatx80_div(floatx80, floatx80, float_status *status);
-floatx80 floatx80_modrem(floatx80, floatx80, bool, float_status *status);
+floatx80 floatx80_modrem(floatx80, floatx80, bool, uint64_t *,
+ float_status *status);
floatx80 floatx80_mod(floatx80, floatx80, float_status *status);
floatx80 floatx80_rem(floatx80, floatx80, float_status *status);
floatx80 floatx80_sqrt(floatx80, float_status *status);
--
2.17.1
--
Joseph S. Myers
jos...@codesourcery.com
