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-rw-r--r--arch/x86/math-emu/reg_add_sub.c563
1 files changed, 261 insertions, 302 deletions
diff --git a/arch/x86/math-emu/reg_add_sub.c b/arch/x86/math-emu/reg_add_sub.c
index 7cd3b37ac084..deea48b9f13a 100644
--- a/arch/x86/math-emu/reg_add_sub.c
+++ b/arch/x86/math-emu/reg_add_sub.c
@@ -27,7 +27,7 @@
static
int add_sub_specials(FPU_REG const *a, u_char taga, u_char signa,
FPU_REG const *b, u_char tagb, u_char signb,
- FPU_REG *dest, int deststnr, int control_w);
+ FPU_REG * dest, int deststnr, int control_w);
/*
Operates on st(0) and st(n), or on st(0) and temporary data.
@@ -35,340 +35,299 @@ int add_sub_specials(FPU_REG const *a, u_char taga, u_char signa,
*/
int FPU_add(FPU_REG const *b, u_char tagb, int deststnr, int control_w)
{
- FPU_REG *a = &st(0);
- FPU_REG *dest = &st(deststnr);
- u_char signb = getsign(b);
- u_char taga = FPU_gettag0();
- u_char signa = getsign(a);
- u_char saved_sign = getsign(dest);
- int diff, tag, expa, expb;
-
- if ( !(taga | tagb) )
- {
- expa = exponent(a);
- expb = exponent(b);
-
- valid_add:
- /* Both registers are valid */
- if (!(signa ^ signb))
- {
- /* signs are the same */
- tag = FPU_u_add(a, b, dest, control_w, signa, expa, expb);
- }
- else
- {
- /* The signs are different, so do a subtraction */
- diff = expa - expb;
- if (!diff)
- {
- diff = a->sigh - b->sigh; /* This works only if the ms bits
- are identical. */
- if (!diff)
- {
- diff = a->sigl > b->sigl;
- if (!diff)
- diff = -(a->sigl < b->sigl);
+ FPU_REG *a = &st(0);
+ FPU_REG *dest = &st(deststnr);
+ u_char signb = getsign(b);
+ u_char taga = FPU_gettag0();
+ u_char signa = getsign(a);
+ u_char saved_sign = getsign(dest);
+ int diff, tag, expa, expb;
+
+ if (!(taga | tagb)) {
+ expa = exponent(a);
+ expb = exponent(b);
+
+ valid_add:
+ /* Both registers are valid */
+ if (!(signa ^ signb)) {
+ /* signs are the same */
+ tag =
+ FPU_u_add(a, b, dest, control_w, signa, expa, expb);
+ } else {
+ /* The signs are different, so do a subtraction */
+ diff = expa - expb;
+ if (!diff) {
+ diff = a->sigh - b->sigh; /* This works only if the ms bits
+ are identical. */
+ if (!diff) {
+ diff = a->sigl > b->sigl;
+ if (!diff)
+ diff = -(a->sigl < b->sigl);
+ }
+ }
+
+ if (diff > 0) {
+ tag =
+ FPU_u_sub(a, b, dest, control_w, signa,
+ expa, expb);
+ } else if (diff < 0) {
+ tag =
+ FPU_u_sub(b, a, dest, control_w, signb,
+ expb, expa);
+ } else {
+ FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
+ /* sign depends upon rounding mode */
+ setsign(dest, ((control_w & CW_RC) != RC_DOWN)
+ ? SIGN_POS : SIGN_NEG);
+ return TAG_Zero;
+ }
}
- }
-
- if (diff > 0)
- {
- tag = FPU_u_sub(a, b, dest, control_w, signa, expa, expb);
- }
- else if ( diff < 0 )
- {
- tag = FPU_u_sub(b, a, dest, control_w, signb, expb, expa);
- }
- else
- {
- FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
- /* sign depends upon rounding mode */
- setsign(dest, ((control_w & CW_RC) != RC_DOWN)
- ? SIGN_POS : SIGN_NEG);
- return TAG_Zero;
- }
- }
- if ( tag < 0 )
- {
- setsign(dest, saved_sign);
- return tag;
+ if (tag < 0) {
+ setsign(dest, saved_sign);
+ return tag;
+ }
+ FPU_settagi(deststnr, tag);
+ return tag;
}
- FPU_settagi(deststnr, tag);
- return tag;
- }
- if ( taga == TAG_Special )
- taga = FPU_Special(a);
- if ( tagb == TAG_Special )
- tagb = FPU_Special(b);
+ if (taga == TAG_Special)
+ taga = FPU_Special(a);
+ if (tagb == TAG_Special)
+ tagb = FPU_Special(b);
- if ( ((taga == TAG_Valid) && (tagb == TW_Denormal))
+ if (((taga == TAG_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
- || ((taga == TW_Denormal) && (tagb == TW_Denormal)) )
- {
- FPU_REG x, y;
+ || ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
+ FPU_REG x, y;
+
+ if (denormal_operand() < 0)
+ return FPU_Exception;
+
+ FPU_to_exp16(a, &x);
+ FPU_to_exp16(b, &y);
+ a = &x;
+ b = &y;
+ expa = exponent16(a);
+ expb = exponent16(b);
+ goto valid_add;
+ }
- if ( denormal_operand() < 0 )
- return FPU_Exception;
+ if ((taga == TW_NaN) || (tagb == TW_NaN)) {
+ if (deststnr == 0)
+ return real_2op_NaN(b, tagb, deststnr, a);
+ else
+ return real_2op_NaN(a, taga, deststnr, a);
+ }
- FPU_to_exp16(a, &x);
- FPU_to_exp16(b, &y);
- a = &x;
- b = &y;
- expa = exponent16(a);
- expb = exponent16(b);
- goto valid_add;
- }
-
- if ( (taga == TW_NaN) || (tagb == TW_NaN) )
- {
- if ( deststnr == 0 )
- return real_2op_NaN(b, tagb, deststnr, a);
- else
- return real_2op_NaN(a, taga, deststnr, a);
- }
-
- return add_sub_specials(a, taga, signa, b, tagb, signb,
- dest, deststnr, control_w);
+ return add_sub_specials(a, taga, signa, b, tagb, signb,
+ dest, deststnr, control_w);
}
-
/* Subtract b from a. (a-b) -> dest */
int FPU_sub(int flags, int rm, int control_w)
{
- FPU_REG const *a, *b;
- FPU_REG *dest;
- u_char taga, tagb, signa, signb, saved_sign, sign;
- int diff, tag = 0, expa, expb, deststnr;
-
- a = &st(0);
- taga = FPU_gettag0();
-
- deststnr = 0;
- if ( flags & LOADED )
- {
- b = (FPU_REG *)rm;
- tagb = flags & 0x0f;
- }
- else
- {
- b = &st(rm);
- tagb = FPU_gettagi(rm);
-
- if ( flags & DEST_RM )
- deststnr = rm;
- }
-
- signa = getsign(a);
- signb = getsign(b);
-
- if ( flags & REV )
- {
- signa ^= SIGN_NEG;
- signb ^= SIGN_NEG;
- }
-
- dest = &st(deststnr);
- saved_sign = getsign(dest);
-
- if ( !(taga | tagb) )
- {
- expa = exponent(a);
- expb = exponent(b);
-
- valid_subtract:
- /* Both registers are valid */
-
- diff = expa - expb;
-
- if (!diff)
- {
- diff = a->sigh - b->sigh; /* Works only if ms bits are identical */
- if (!diff)
- {
- diff = a->sigl > b->sigl;
- if (!diff)
- diff = -(a->sigl < b->sigl);
- }
+ FPU_REG const *a, *b;
+ FPU_REG *dest;
+ u_char taga, tagb, signa, signb, saved_sign, sign;
+ int diff, tag = 0, expa, expb, deststnr;
+
+ a = &st(0);
+ taga = FPU_gettag0();
+
+ deststnr = 0;
+ if (flags & LOADED) {
+ b = (FPU_REG *) rm;
+ tagb = flags & 0x0f;
+ } else {
+ b = &st(rm);
+ tagb = FPU_gettagi(rm);
+
+ if (flags & DEST_RM)
+ deststnr = rm;
}
- switch ( (((int)signa)*2 + signb) / SIGN_NEG )
- {
- case 0: /* P - P */
- case 3: /* N - N */
- if (diff > 0)
- {
- /* |a| > |b| */
- tag = FPU_u_sub(a, b, dest, control_w, signa, expa, expb);
- }
- else if ( diff == 0 )
- {
- FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
-
- /* sign depends upon rounding mode */
- setsign(dest, ((control_w & CW_RC) != RC_DOWN)
- ? SIGN_POS : SIGN_NEG);
- return TAG_Zero;
- }
- else
- {
- sign = signa ^ SIGN_NEG;
- tag = FPU_u_sub(b, a, dest, control_w, sign, expb, expa);
- }
- break;
- case 1: /* P - N */
- tag = FPU_u_add(a, b, dest, control_w, SIGN_POS, expa, expb);
- break;
- case 2: /* N - P */
- tag = FPU_u_add(a, b, dest, control_w, SIGN_NEG, expa, expb);
- break;
+ signa = getsign(a);
+ signb = getsign(b);
+
+ if (flags & REV) {
+ signa ^= SIGN_NEG;
+ signb ^= SIGN_NEG;
+ }
+
+ dest = &st(deststnr);
+ saved_sign = getsign(dest);
+
+ if (!(taga | tagb)) {
+ expa = exponent(a);
+ expb = exponent(b);
+
+ valid_subtract:
+ /* Both registers are valid */
+
+ diff = expa - expb;
+
+ if (!diff) {
+ diff = a->sigh - b->sigh; /* Works only if ms bits are identical */
+ if (!diff) {
+ diff = a->sigl > b->sigl;
+ if (!diff)
+ diff = -(a->sigl < b->sigl);
+ }
+ }
+
+ switch ((((int)signa) * 2 + signb) / SIGN_NEG) {
+ case 0: /* P - P */
+ case 3: /* N - N */
+ if (diff > 0) {
+ /* |a| > |b| */
+ tag =
+ FPU_u_sub(a, b, dest, control_w, signa,
+ expa, expb);
+ } else if (diff == 0) {
+ FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
+
+ /* sign depends upon rounding mode */
+ setsign(dest, ((control_w & CW_RC) != RC_DOWN)
+ ? SIGN_POS : SIGN_NEG);
+ return TAG_Zero;
+ } else {
+ sign = signa ^ SIGN_NEG;
+ tag =
+ FPU_u_sub(b, a, dest, control_w, sign, expb,
+ expa);
+ }
+ break;
+ case 1: /* P - N */
+ tag =
+ FPU_u_add(a, b, dest, control_w, SIGN_POS, expa,
+ expb);
+ break;
+ case 2: /* N - P */
+ tag =
+ FPU_u_add(a, b, dest, control_w, SIGN_NEG, expa,
+ expb);
+ break;
#ifdef PARANOID
- default:
- EXCEPTION(EX_INTERNAL|0x111);
- return -1;
+ default:
+ EXCEPTION(EX_INTERNAL | 0x111);
+ return -1;
#endif
+ }
+ if (tag < 0) {
+ setsign(dest, saved_sign);
+ return tag;
+ }
+ FPU_settagi(deststnr, tag);
+ return tag;
}
- if ( tag < 0 )
- {
- setsign(dest, saved_sign);
- return tag;
- }
- FPU_settagi(deststnr, tag);
- return tag;
- }
- if ( taga == TAG_Special )
- taga = FPU_Special(a);
- if ( tagb == TAG_Special )
- tagb = FPU_Special(b);
+ if (taga == TAG_Special)
+ taga = FPU_Special(a);
+ if (tagb == TAG_Special)
+ tagb = FPU_Special(b);
- if ( ((taga == TAG_Valid) && (tagb == TW_Denormal))
+ if (((taga == TAG_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
- || ((taga == TW_Denormal) && (tagb == TW_Denormal)) )
- {
- FPU_REG x, y;
+ || ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
+ FPU_REG x, y;
- if ( denormal_operand() < 0 )
- return FPU_Exception;
+ if (denormal_operand() < 0)
+ return FPU_Exception;
+
+ FPU_to_exp16(a, &x);
+ FPU_to_exp16(b, &y);
+ a = &x;
+ b = &y;
+ expa = exponent16(a);
+ expb = exponent16(b);
- FPU_to_exp16(a, &x);
- FPU_to_exp16(b, &y);
- a = &x;
- b = &y;
- expa = exponent16(a);
- expb = exponent16(b);
-
- goto valid_subtract;
- }
-
- if ( (taga == TW_NaN) || (tagb == TW_NaN) )
- {
- FPU_REG const *d1, *d2;
- if ( flags & REV )
- {
- d1 = b;
- d2 = a;
+ goto valid_subtract;
}
- else
- {
- d1 = a;
- d2 = b;
+
+ if ((taga == TW_NaN) || (tagb == TW_NaN)) {
+ FPU_REG const *d1, *d2;
+ if (flags & REV) {
+ d1 = b;
+ d2 = a;
+ } else {
+ d1 = a;
+ d2 = b;
+ }
+ if (flags & LOADED)
+ return real_2op_NaN(b, tagb, deststnr, d1);
+ if (flags & DEST_RM)
+ return real_2op_NaN(a, taga, deststnr, d2);
+ else
+ return real_2op_NaN(b, tagb, deststnr, d2);
}
- if ( flags & LOADED )
- return real_2op_NaN(b, tagb, deststnr, d1);
- if ( flags & DEST_RM )
- return real_2op_NaN(a, taga, deststnr, d2);
- else
- return real_2op_NaN(b, tagb, deststnr, d2);
- }
-
- return add_sub_specials(a, taga, signa, b, tagb, signb ^ SIGN_NEG,
- dest, deststnr, control_w);
-}
+ return add_sub_specials(a, taga, signa, b, tagb, signb ^ SIGN_NEG,
+ dest, deststnr, control_w);
+}
static
int add_sub_specials(FPU_REG const *a, u_char taga, u_char signa,
FPU_REG const *b, u_char tagb, u_char signb,
- FPU_REG *dest, int deststnr, int control_w)
+ FPU_REG * dest, int deststnr, int control_w)
{
- if ( ((taga == TW_Denormal) || (tagb == TW_Denormal))
- && (denormal_operand() < 0) )
- return FPU_Exception;
-
- if (taga == TAG_Zero)
- {
- if (tagb == TAG_Zero)
- {
- /* Both are zero, result will be zero. */
- u_char different_signs = signa ^ signb;
-
- FPU_copy_to_regi(a, TAG_Zero, deststnr);
- if ( different_signs )
- {
- /* Signs are different. */
- /* Sign of answer depends upon rounding mode. */
- setsign(dest, ((control_w & CW_RC) != RC_DOWN)
- ? SIGN_POS : SIGN_NEG);
- }
- else
- setsign(dest, signa); /* signa may differ from the sign of a. */
- return TAG_Zero;
- }
- else
- {
- reg_copy(b, dest);
- if ( (tagb == TW_Denormal) && (b->sigh & 0x80000000) )
- {
- /* A pseudoDenormal, convert it. */
- addexponent(dest, 1);
- tagb = TAG_Valid;
- }
- else if ( tagb > TAG_Empty )
- tagb = TAG_Special;
- setsign(dest, signb); /* signb may differ from the sign of b. */
- FPU_settagi(deststnr, tagb);
- return tagb;
- }
- }
- else if (tagb == TAG_Zero)
- {
- reg_copy(a, dest);
- if ( (taga == TW_Denormal) && (a->sigh & 0x80000000) )
- {
- /* A pseudoDenormal */
- addexponent(dest, 1);
- taga = TAG_Valid;
- }
- else if ( taga > TAG_Empty )
- taga = TAG_Special;
- setsign(dest, signa); /* signa may differ from the sign of a. */
- FPU_settagi(deststnr, taga);
- return taga;
- }
- else if (taga == TW_Infinity)
- {
- if ( (tagb != TW_Infinity) || (signa == signb) )
- {
- FPU_copy_to_regi(a, TAG_Special, deststnr);
- setsign(dest, signa); /* signa may differ from the sign of a. */
- return taga;
+ if (((taga == TW_Denormal) || (tagb == TW_Denormal))
+ && (denormal_operand() < 0))
+ return FPU_Exception;
+
+ if (taga == TAG_Zero) {
+ if (tagb == TAG_Zero) {
+ /* Both are zero, result will be zero. */
+ u_char different_signs = signa ^ signb;
+
+ FPU_copy_to_regi(a, TAG_Zero, deststnr);
+ if (different_signs) {
+ /* Signs are different. */
+ /* Sign of answer depends upon rounding mode. */
+ setsign(dest, ((control_w & CW_RC) != RC_DOWN)
+ ? SIGN_POS : SIGN_NEG);
+ } else
+ setsign(dest, signa); /* signa may differ from the sign of a. */
+ return TAG_Zero;
+ } else {
+ reg_copy(b, dest);
+ if ((tagb == TW_Denormal) && (b->sigh & 0x80000000)) {
+ /* A pseudoDenormal, convert it. */
+ addexponent(dest, 1);
+ tagb = TAG_Valid;
+ } else if (tagb > TAG_Empty)
+ tagb = TAG_Special;
+ setsign(dest, signb); /* signb may differ from the sign of b. */
+ FPU_settagi(deststnr, tagb);
+ return tagb;
+ }
+ } else if (tagb == TAG_Zero) {
+ reg_copy(a, dest);
+ if ((taga == TW_Denormal) && (a->sigh & 0x80000000)) {
+ /* A pseudoDenormal */
+ addexponent(dest, 1);
+ taga = TAG_Valid;
+ } else if (taga > TAG_Empty)
+ taga = TAG_Special;
+ setsign(dest, signa); /* signa may differ from the sign of a. */
+ FPU_settagi(deststnr, taga);
+ return taga;
+ } else if (taga == TW_Infinity) {
+ if ((tagb != TW_Infinity) || (signa == signb)) {
+ FPU_copy_to_regi(a, TAG_Special, deststnr);
+ setsign(dest, signa); /* signa may differ from the sign of a. */
+ return taga;
+ }
+ /* Infinity-Infinity is undefined. */
+ return arith_invalid(deststnr);
+ } else if (tagb == TW_Infinity) {
+ FPU_copy_to_regi(b, TAG_Special, deststnr);
+ setsign(dest, signb); /* signb may differ from the sign of b. */
+ return tagb;
}
- /* Infinity-Infinity is undefined. */
- return arith_invalid(deststnr);
- }
- else if (tagb == TW_Infinity)
- {
- FPU_copy_to_regi(b, TAG_Special, deststnr);
- setsign(dest, signb); /* signb may differ from the sign of b. */
- return tagb;
- }
-
#ifdef PARANOID
- EXCEPTION(EX_INTERNAL|0x101);
+ EXCEPTION(EX_INTERNAL | 0x101);
#endif
- return FPU_Exception;
+ return FPU_Exception;
}
-
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.