static void
fsqrt_(void)
{
if (!(FPU_st0_tag ^ TW_Valid)) {
int expon;
if (FPU_st0_ptr->sign == SIGN_NEG) {
arith_invalid(FPU_st0_ptr); /* sqrt(negative) is
* invalid */
return;
}
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return;
#endif /* DENORM_OPERAND */
expon = FPU_st0_ptr->exp - EXP_BIAS;
FPU_st0_ptr->exp = EXP_BIAS + (expon & 1); /* make st(0) in [1.0
* .. 4.0) */
wm_sqrt(FPU_st0_ptr, control_word); /* Do the computation */
FPU_st0_ptr->exp += expon >> 1;
FPU_st0_ptr->sign = SIGN_POS;
} else if (FPU_st0_tag == TW_Zero)
static void
fptan(void)
{
FPU_REG *st_new_ptr;
int q;
char arg_sign = FPU_st0_ptr->sign;
if (STACK_OVERFLOW) {
stack_overflow();
return;
}
switch (FPU_st0_tag) {
case TW_Valid:
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return;
#endif /* DENORM_OPERAND */
FPU_st0_ptr->sign = SIGN_POS;
if ((q = trig_arg(FPU_st0_ptr)) != -1) {
if (q & 1)
reg_sub(&CONST_1, FPU_st0_ptr, FPU_st0_ptr, FULL_PRECISION);
poly_tan(FPU_st0_ptr, FPU_st0_ptr);
FPU_st0_ptr->sign = (q & 1) ^ arg_sign;
if (FPU_st0_ptr->exp <= EXP_UNDER)
arith_underflow(FPU_st0_ptr);
push();
reg_move(&CONST_1, FPU_st0_ptr);
setcc(0);
} else {
/* Operand is out of range */
setcc(SW_C2);
FPU_st0_ptr->sign = arg_sign; /* restore st(0) */
return;
}
break;
case TW_Infinity:
/* Operand is out of range */
setcc(SW_C2);
FPU_st0_ptr->sign = arg_sign; /* restore st(0) */
return;
case TW_Zero:
push();
reg_move(&CONST_1, FPU_st0_ptr);
setcc(0);
break;
default:
single_arg_error();
break;
}
}
static void ftst_(FPU_REG *st0_ptr, u_char st0tag)
{
switch (st0tag)
{
case TAG_Zero:
setcc(SW_C3);
break;
case TAG_Valid:
if (getsign(st0_ptr) == SIGN_POS)
setcc(0);
else
setcc(SW_C0);
break;
case TAG_Special:
switch ( FPU_Special(st0_ptr) )
{
case TW_Denormal:
if (getsign(st0_ptr) == SIGN_POS)
setcc(0);
else
setcc(SW_C0);
if ( denormal_operand() < 0 )
{
#ifdef PECULIAR_486
/* This is weird! */
if (getsign(st0_ptr) == SIGN_POS)
setcc(SW_C3);
#endif /* PECULIAR_486 */
return;
}
break;
case TW_NaN:
setcc(SW_C0|SW_C2|SW_C3); /* Operand is not comparable */
EXCEPTION(EX_Invalid);
break;
case TW_Infinity:
if (getsign(st0_ptr) == SIGN_POS)
setcc(0);
else
setcc(SW_C0);
break;
default:
setcc(SW_C0|SW_C2|SW_C3); /* Operand is not comparable */
EXCEPTION(EX_INTERNAL|0x14);
break;
}
break;
case TAG_Empty:
setcc(SW_C0|SW_C2|SW_C3);
EXCEPTION(EX_StackUnder);
break;
}
}
static int compare_u_st_st(int nr)
{
int f = 0, c;
FPU_REG *st_ptr;
if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
setcc(SW_C3 | SW_C2 | SW_C0);
/* */
EXCEPTION(EX_StackUnder);
return !(control_word & CW_Invalid);
}
st_ptr = &st(nr);
c = compare(st_ptr, FPU_gettagi(nr));
if (c & COMP_NaN) {
setcc(SW_C3 | SW_C2 | SW_C0);
if (c & COMP_SNaN) { /*
*/
EXCEPTION(EX_Invalid);
return !(control_word & CW_Invalid);
}
return 0;
} else
switch (c & 7) {
case COMP_A_lt_B:
f = SW_C0;
break;
case COMP_A_eq_B:
f = SW_C3;
break;
case COMP_A_gt_B:
f = 0;
break;
case COMP_No_Comp:
f = SW_C3 | SW_C2 | SW_C0;
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x123);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* */
}
setcc(f);
if (c & COMP_Denormal) {
return denormal_operand() < 0;
}
return 0;
}
static void
f2xm1(void)
{
switch (FPU_st0_tag) {
case TW_Valid:
{
FPU_REG rv, tmp;
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return;
#endif /* DENORM_OPERAND */
if (FPU_st0_ptr->sign == SIGN_POS) {
/* poly_2xm1(x) requires 0 < x < 1. */
if (poly_2xm1(FPU_st0_ptr, &rv))
return; /* error */
reg_mul(&rv, FPU_st0_ptr, FPU_st0_ptr, FULL_PRECISION);
} else {
/* **** Should change poly_2xm1() to at least handle numbers near 0 */
/* poly_2xm1(x) doesn't handle negative
* numbers. */
/* So we compute (poly_2xm1(x+1)-1)/2, for -1
* < x < 0 */
reg_add(FPU_st0_ptr, &CONST_1, &tmp, FULL_PRECISION);
poly_2xm1(&tmp, &rv);
reg_mul(&rv, &tmp, &tmp, FULL_PRECISION);
reg_sub(&tmp, &CONST_1, FPU_st0_ptr, FULL_PRECISION);
FPU_st0_ptr->exp--;
if (FPU_st0_ptr->exp <= EXP_UNDER)
arith_underflow(FPU_st0_ptr);
}
return;
}
case TW_Zero:
return;
case TW_Infinity:
if (FPU_st0_ptr->sign == SIGN_NEG) {
/* -infinity gives -1 (p16-10) */
reg_move(&CONST_1, FPU_st0_ptr);
FPU_st0_ptr->sign = SIGN_NEG;
}
return;
default:
single_arg_error();
}
}
static void f2xm1(FPU_REG *st0_ptr, u_char tag)
{
FPU_REG a;
clear_C1();
if ( tag == TAG_Valid )
{
/* For an 80486 FPU, the result is undefined if the arg is >= 1.0 */
if ( exponent(st0_ptr) < 0 )
{
denormal_arg:
FPU_to_exp16(st0_ptr, &a);
/* poly_2xm1(x) requires 0 < st(0) < 1. */
poly_2xm1(getsign(st0_ptr), &a, st0_ptr);
}
set_precision_flag_up(); /* 80486 appears to always do this */
return;
}
if ( tag == TAG_Zero )
return;
if ( tag == TAG_Special )
tag = FPU_Special(st0_ptr);
switch ( tag )
{
case TW_Denormal:
if ( denormal_operand() < 0 )
return;
goto denormal_arg;
case TW_Infinity:
if ( signnegative(st0_ptr) )
{
/* -infinity gives -1 (p16-10) */
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
setnegative(st0_ptr);
}
return;
default:
single_arg_error(st0_ptr, tag);
}
}
static void f2xm1(FPU_REG *st0_ptr, u_char tag)
{
FPU_REG a;
clear_C1();
if (tag == TAG_Valid) {
if (exponent(st0_ptr) < 0) {
denormal_arg:
FPU_to_exp16(st0_ptr, &a);
poly_2xm1(getsign(st0_ptr), &a, st0_ptr);
}
set_precision_flag_up();
return;
}
if (tag == TAG_Zero)
return;
if (tag == TAG_Special)
tag = FPU_Special(st0_ptr);
switch (tag) {
case TW_Denormal:
if (denormal_operand() < 0)
return;
goto denormal_arg;
case TW_Infinity:
if (signnegative(st0_ptr)) {
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
setnegative(st0_ptr);
}
return;
default:
single_arg_error(st0_ptr, tag);
}
}
static void
ftst_(void)
{
switch (FPU_st0_tag) {
case TW_Zero:
setcc(SW_C3);
break;
case TW_Valid:
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return;
#endif /* DENORM_OPERAND */
if (FPU_st0_ptr->sign == SIGN_POS)
setcc(0);
else
setcc(SW_C0);
break;
case TW_NaN:
setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
EXCEPTION(EX_Invalid);
break;
case TW_Infinity:
if (FPU_st0_ptr->sign == SIGN_POS)
setcc(0);
else
setcc(SW_C0);
EXCEPTION(EX_Invalid);
break;
case TW_Empty:
setcc(SW_C0 | SW_C2 | SW_C3);
EXCEPTION(EX_StackUnder);
break;
default:
setcc(SW_C0 | SW_C2 | SW_C3); /* Operand is not comparable */
EXCEPTION(EX_INTERNAL | 0x14);
break;
}
}
int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag)
{
int f = 0, c;
c = compare(loaded_data, loaded_tag);
if (c & COMP_NaN) {
EXCEPTION(EX_Invalid);
f = SW_C3 | SW_C2 | SW_C0;
} else
switch (c & 7) {
case COMP_A_lt_B:
f = SW_C0;
break;
case COMP_A_eq_B:
f = SW_C3;
break;
case COMP_A_gt_B:
f = 0;
break;
case COMP_No_Comp:
f = SW_C3 | SW_C2 | SW_C0;
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x121);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* */
}
setcc(f);
if (c & COMP_Denormal) {
return denormal_operand() < 0;
}
return 0;
}
int FPU_mul(FPU_REG const *b, u_char tagb, int deststnr, int control_w)
{
FPU_REG *a = &st(deststnr);
FPU_REG *dest = a;
u_char taga = FPU_gettagi(deststnr);
u_char saved_sign = getsign(dest);
u_char sign = (getsign(a) ^ getsign(b));
int tag;
if (!(taga | tagb)) {
tag =
FPU_u_mul(a, b, dest, control_w, sign,
exponent(a) + exponent(b));
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((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);
tag = FPU_u_mul(&x, &y, dest, control_w, sign,
exponent16(&x) + exponent16(&y));
if (tag < 0) {
setsign(dest, saved_sign);
return tag;
}
FPU_settagi(deststnr, tag);
return tag;
} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
if (((tagb == TW_Denormal) || (taga == TW_Denormal))
&& (denormal_operand() < 0))
return FPU_Exception;
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
return real_2op_NaN(b, tagb, deststnr, &st(0));
} else if (((taga == TW_Infinity) && (tagb == TAG_Zero))
|| ((tagb == TW_Infinity) && (taga == TAG_Zero))) {
return arith_invalid(deststnr);
} else if (((taga == TW_Denormal) || (tagb == TW_Denormal))
&& (denormal_operand() < 0)) {
return FPU_Exception;
} else if (taga == TW_Infinity) {
FPU_copy_to_regi(a, TAG_Special, deststnr);
setsign(dest, sign);
return TAG_Special;
} else if (tagb == TW_Infinity) {
FPU_copy_to_regi(b, TAG_Special, deststnr);
setsign(dest, sign);
return TAG_Special;
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x102);
return FPU_Exception;
}
#endif
return 0;
}
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)
{
if (((taga == TW_Denormal) || (tagb == TW_Denormal))
&& (denormal_operand() < 0))
return FPU_Exception;
if (taga == TAG_Zero) {
if (tagb == TAG_Zero) {
u_char different_signs = signa ^ signb;
FPU_copy_to_regi(a, TAG_Zero, deststnr);
if (different_signs) {
setsign(dest, ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG);
} else
setsign(dest, signa);
return TAG_Zero;
} else {
reg_copy(b, dest);
if ((tagb == TW_Denormal) && (b->sigh & 0x80000000)) {
addexponent(dest, 1);
tagb = TAG_Valid;
} else if (tagb > TAG_Empty)
tagb = TAG_Special;
setsign(dest, signb);
FPU_settagi(deststnr, tagb);
return tagb;
}
} else if (tagb == TAG_Zero) {
reg_copy(a, dest);
if ((taga == TW_Denormal) && (a->sigh & 0x80000000)) {
addexponent(dest, 1);
taga = TAG_Valid;
} else if (taga > TAG_Empty)
taga = TAG_Special;
setsign(dest, signa);
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);
return taga;
}
return arith_invalid(deststnr);
} else if (tagb == TW_Infinity) {
FPU_copy_to_regi(b, TAG_Special, deststnr);
setsign(dest, signb);
return tagb;
}
#ifdef PARANOID
EXCEPTION(EX_INTERNAL | 0x101);
#endif
return FPU_Exception;
}
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:
if (!(signa ^ signb)) {
tag =
FPU_u_add(a, b, dest, control_w, signa, expa, expb);
} else {
diff = expa - expb;
if (!diff) {
diff = a->sigh - b->sigh;
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);
setsign(dest, ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG);
return TAG_Zero;
}
}
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((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 ((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);
}
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:
diff = expa - expb;
if (!diff) {
diff = a->sigh - b->sigh;
if (!diff) {
diff = a->sigl > b->sigl;
if (!diff)
diff = -(a->sigl < b->sigl);
}
}
switch ((((int)signa) * 2 + signb) / SIGN_NEG) {
case 0:
case 3:
if (diff > 0) {
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);
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:
tag =
FPU_u_add(a, b, dest, control_w, SIGN_POS, expa,
expb);
break;
case 2:
tag =
FPU_u_add(a, b, dest, control_w, SIGN_NEG, expa,
expb);
break;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x111);
return -1;
#endif
}
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((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_subtract;
}
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);
}
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)
{
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;
}
#ifdef PARANOID
EXCEPTION(EX_INTERNAL|0x101);
#endif
return FPU_Exception;
}
void
reg_add(FPU_REG * a, FPU_REG * b, FPU_REG * dest, int control_w)
{
int diff;
if (!(a->tag | b->tag)) {
/* Both registers are valid */
if (!(a->sign ^ b->sign)) {
/* signs are the same */
reg_u_add(a, b, dest, control_w);
dest->sign = a->sign;
return;
}
/* The signs are different, so do a subtraction */
diff = a->exp - b->exp;
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);
}
}
if (diff > 0) {
reg_u_sub(a, b, dest, control_w);
dest->sign = a->sign;
} else
if (diff == 0) {
reg_move(&CONST_Z, dest);
/* sign depends upon rounding mode */
dest->sign = ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG;
} else {
reg_u_sub(b, a, dest, control_w);
dest->sign = b->sign;
}
return;
} else {
if ((a->tag == TW_NaN) || (b->tag == TW_NaN)) {
real_2op_NaN(a, b, dest);
return;
} else
if (a->tag == TW_Zero) {
if (b->tag == TW_Zero) {
char different_signs = a->sign ^ b->sign;
/* Both are zero, result will be zero. */
reg_move(a, dest);
if (different_signs) {
/* Signs are different. */
/* Sign of answer depends upon
* rounding mode. */
dest->sign = ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG;
}
} else {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(b, dest);
}
return;
} else
if (b->tag == TW_Zero) {
#ifdef DENORM_OPERAND
if ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(a, dest);
return;
} else
if (a->tag == TW_Infinity) {
if (b->tag != TW_Infinity) {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(a, dest);
return;
}
if (a->sign == b->sign) {
/* They are both + or
* - infinity */
reg_move(a, dest);
return;
}
arith_invalid(dest); /* Infinity-Infinity is
* undefined. */
return;
} else
if (b->tag == TW_Infinity) {
#ifdef DENORM_OPERAND
if ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(b, dest);
return;
}
}
#ifdef PARANOID
EXCEPTION(EX_INTERNAL | 0x101);
#endif
}
static void fptan(FPU_REG *st0_ptr, u_char st0_tag)
{
FPU_REG *st_new_ptr;
int q;
u_char arg_sign = getsign(st0_ptr);
/* Stack underflow has higher priority */
if (st0_tag == TAG_Empty) {
FPU_stack_underflow(); /* Puts a QNaN in st(0) */
if (control_word & CW_Invalid) {
st_new_ptr = &st(-1);
push();
FPU_stack_underflow(); /* Puts a QNaN in the new st(0) */
}
return;
}
if (STACK_OVERFLOW) {
FPU_stack_overflow();
return;
}
if (st0_tag == TAG_Valid) {
if (exponent(st0_ptr) > -40) {
if ((q = trig_arg(st0_ptr, 0)) == -1) {
/* Operand is out of range */
return;
}
poly_tan(st0_ptr);
setsign(st0_ptr, (q & 1) ^ (arg_sign != 0));
set_precision_flag_up(); /* We do not really know if up or down */
} else {
/* For a small arg, the result == the argument */
/* Underflow may happen */
denormal_arg:
FPU_to_exp16(st0_ptr, st0_ptr);
st0_tag =
FPU_round(st0_ptr, 1, 0, FULL_PRECISION, arg_sign);
FPU_settag0(st0_tag);
}
push();
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
return;
}
if (st0_tag == TAG_Zero) {
push();
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
setcc(0);
return;
}
if (st0_tag == TAG_Special)
st0_tag = FPU_Special(st0_ptr);
if (st0_tag == TW_Denormal) {
if (denormal_operand() < 0)
return;
goto denormal_arg;
}
if (st0_tag == TW_Infinity) {
/* The 80486 treats infinity as an invalid operand */
if (arith_invalid(0) >= 0) {
st_new_ptr = &st(-1);
push();
arith_invalid(0);
}
return;
}
single_arg_2_error(st0_ptr, st0_tag);
}
/*
Operates on st(0) and st(n), or on st(0) and temporary data.
The destination must be one of the source st(x).
*/
int FPU_add(FPU_REG const *b, u_char tagb, int deststnr, u16 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);
}
}
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;
}
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((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 ( (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);
}
/*
Divide one register by another and put the result into a third register.
*/
int FPU_div(int flags, int rm, int control_w)
{
FPU_REG x, y;
FPU_REG const *a, *b, *st0_ptr, *st_ptr;
FPU_REG *dest;
u_char taga, tagb, signa, signb, sign, saved_sign;
int tag, deststnr;
if (flags & DEST_RM)
deststnr = rm;
else
deststnr = 0;
if (flags & REV) {
b = &st(0);
st0_ptr = b;
tagb = FPU_gettag0();
if (flags & LOADED) {
a = (FPU_REG *) rm;
taga = flags & 0x0f;
} else {
a = &st(rm);
st_ptr = a;
taga = FPU_gettagi(rm);
}
} else {
a = &st(0);
st0_ptr = a;
taga = FPU_gettag0();
if (flags & LOADED) {
b = (FPU_REG *) rm;
tagb = flags & 0x0f;
} else {
b = &st(rm);
st_ptr = b;
tagb = FPU_gettagi(rm);
}
}
signa = getsign(a);
signb = getsign(b);
sign = signa ^ signb;
dest = &st(deststnr);
saved_sign = getsign(dest);
if (!(taga | tagb)) {
/* Both regs Valid, this should be the most common case. */
reg_copy(a, &x);
reg_copy(b, &y);
setpositive(&x);
setpositive(&y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
if (denormal_operand() < 0)
return FPU_Exception;
FPU_to_exp16(a, &x);
FPU_to_exp16(b, &y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
return tag;
FPU_settagi(deststnr, tag);
return tag;
} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
if (tagb != TAG_Zero) {
/* Want to find Zero/Valid */
if (tagb == TW_Denormal) {
if (denormal_operand() < 0)
return FPU_Exception;
}
/* The result is zero. */
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
/* We have an exception condition, either 0/0 or Valid/Zero. */
if (taga == TAG_Zero) {
/* 0/0 */
return arith_invalid(deststnr);
}
/* Valid/Zero */
return FPU_divide_by_zero(deststnr, sign);
}
/* Must have infinities, NaNs, etc */
else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
if (flags & LOADED)
return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0,
st0_ptr);
if (flags & DEST_RM) {
int tag;
tag = FPU_gettag0();
if (tag == TAG_Special)
tag = FPU_Special(st0_ptr);
return real_2op_NaN(st0_ptr, tag, rm,
(flags & REV) ? st0_ptr : &st(rm));
} else {
int tag;
tag = FPU_gettagi(rm);
if (tag == TAG_Special)
tag = FPU_Special(&st(rm));
return real_2op_NaN(&st(rm), tag, 0,
(flags & REV) ? st0_ptr : &st(rm));
}
} else if (taga == TW_Infinity) {
if (tagb == TW_Infinity) {
/* infinity/infinity */
return arith_invalid(deststnr);
} else {
/* tagb must be Valid or Zero */
if ((tagb == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
/* Infinity divided by Zero or Valid does
not raise and exception, but returns Infinity */
FPU_copy_to_regi(a, TAG_Special, deststnr);
setsign(dest, sign);
return taga;
}
} else if (tagb == TW_Infinity) {
if ((taga == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
/* The result is zero. */
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x102);
return FPU_Exception;
}
#endif /* PARANOID */
return 0;
}
/* Subtract b from a. (a-b) -> dest */
void
reg_sub(FPU_REG * a, FPU_REG * b, FPU_REG * dest, int control_w)
{
int diff;
if (!(a->tag | b->tag)) {
/* Both registers are valid */
diff = a->exp - b->exp;
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 (a->sign * 2 + b->sign) {
case 0: /* P - P */
case 3: /* N - N */
if (diff > 0) {
reg_u_sub(a, b, dest, control_w);
dest->sign = a->sign;
} else
if (diff == 0) {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(&CONST_Z, dest);
/* sign depends upon rounding mode */
dest->sign = ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG;
} else {
reg_u_sub(b, a, dest, control_w);
dest->sign = a->sign ^ SIGN_POS ^ SIGN_NEG;
}
return;
case 1: /* P - N */
reg_u_add(a, b, dest, control_w);
dest->sign = SIGN_POS;
return;
case 2: /* N - P */
reg_u_add(a, b, dest, control_w);
dest->sign = SIGN_NEG;
return;
}
} else {
if ((a->tag == TW_NaN) || (b->tag == TW_NaN)) {
real_2op_NaN(a, b, dest);
return;
} else
if (b->tag == TW_Zero) {
if (a->tag == TW_Zero) {
char same_signs = !(a->sign ^ b->sign);
/* Both are zero, result will be zero. */
reg_move(a, dest); /* Answer for different
* signs. */
if (same_signs) {
/* Sign depends upon rounding
* mode */
dest->sign = ((control_w & CW_RC) != RC_DOWN)
? SIGN_POS : SIGN_NEG;
}
} else {
#ifdef DENORM_OPERAND
if ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(a, dest);
}
return;
} else
if (a->tag == TW_Zero) {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(b, dest);
dest->sign ^= SIGN_POS ^ SIGN_NEG;
return;
} else
if (a->tag == TW_Infinity) {
if (b->tag != TW_Infinity) {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(a, dest);
return;
}
/* Both args are Infinity */
if (a->sign == b->sign) {
arith_invalid(dest); /* Infinity-Infinity is
* undefined. */
return;
}
reg_move(a, dest);
return;
} else
if (b->tag == TW_Infinity) {
#ifdef DENORM_OPERAND
if ((a->tag == TW_Valid) && (a->exp <= EXP_UNDER) &&
denormal_operand())
return;
#endif /* DENORM_OPERAND */
reg_move(b, dest);
dest->sign ^= SIGN_POS ^ SIGN_NEG;
return;
}
}
#ifdef PARANOID
EXCEPTION(EX_INTERNAL | 0x110);
#endif
}
static void fptan(FPU_REG *st0_ptr, u_char st0_tag)
{
FPU_REG *st_new_ptr;
int q;
u_char arg_sign = getsign(st0_ptr);
if (st0_tag == TAG_Empty) {
FPU_stack_underflow();
if (control_word & CW_Invalid) {
st_new_ptr = &st(-1);
push();
FPU_stack_underflow();
}
return;
}
if (STACK_OVERFLOW) {
FPU_stack_overflow();
return;
}
if (st0_tag == TAG_Valid) {
if (exponent(st0_ptr) > -40) {
if ((q = trig_arg(st0_ptr, 0)) == -1) {
return;
}
poly_tan(st0_ptr);
setsign(st0_ptr, (q & 1) ^ (arg_sign != 0));
set_precision_flag_up();
} else {
denormal_arg:
FPU_to_exp16(st0_ptr, st0_ptr);
st0_tag =
FPU_round(st0_ptr, 1, 0, FULL_PRECISION, arg_sign);
FPU_settag0(st0_tag);
}
push();
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
return;
}
if (st0_tag == TAG_Zero) {
push();
FPU_copy_to_reg0(&CONST_1, TAG_Valid);
setcc(0);
return;
}
if (st0_tag == TAG_Special)
st0_tag = FPU_Special(st0_ptr);
if (st0_tag == TW_Denormal) {
if (denormal_operand() < 0)
return;
goto denormal_arg;
}
if (st0_tag == TW_Infinity) {
if (arith_invalid(0) >= 0) {
st_new_ptr = &st(-1);
push();
arith_invalid(0);
}
return;
}
single_arg_2_error(st0_ptr, st0_tag);
}
static void
fxtract(void)
{
FPU_REG *st_new_ptr;
register FPU_REG *st1_ptr = FPU_st0_ptr; /* anticipate */
if (STACK_OVERFLOW) {
stack_overflow();
return;
}
if (!(FPU_st0_tag ^ TW_Valid)) {
long e;
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return;
#endif /* DENORM_OPERAND */
push();
reg_move(st1_ptr, FPU_st0_ptr);
FPU_st0_ptr->exp = EXP_BIAS;
e = st1_ptr->exp - EXP_BIAS;
convert_l2reg(&e, st1_ptr);
return;
} else if (FPU_st0_tag == TW_Zero) {
char sign = FPU_st0_ptr->sign;
divide_by_zero(SIGN_NEG, FPU_st0_ptr);
push();
reg_move(&CONST_Z, FPU_st0_ptr);
FPU_st0_ptr->sign = sign;
return;
} else if (FPU_st0_tag == TW_Infinity) {
char sign = FPU_st0_ptr->sign;
FPU_st0_ptr->sign = SIGN_POS;
push();
reg_move(&CONST_INF, FPU_st0_ptr);
FPU_st0_ptr->sign = sign;
return;
} else if (FPU_st0_tag == TW_NaN) {
if (!(FPU_st0_ptr->sigh & 0x40000000)) { /* Signaling ? */
EXCEPTION(EX_Invalid);
/* Convert to a QNaN */
FPU_st0_ptr->sigh |= 0x40000000;
}
push();
reg_move(st1_ptr, FPU_st0_ptr);
return;
} else if (FPU_st0_tag == TW_Empty) {
/* Is this the correct
* behaviour? */
if (control_word & EX_Invalid) {
stack_underflow();
push();
stack_underflow();
} else
EXCEPTION(EX_StackUnder);
}
#ifdef PARANOID
else
EXCEPTION(EX_INTERNAL | 0x119);
#endif /* PARANOID */
}
static void fxtract(FPU_REG *st0_ptr, u_char st0_tag)
{
FPU_REG *st_new_ptr;
u_char sign;
register FPU_REG *st1_ptr = st0_ptr;
if (STACK_OVERFLOW) {
FPU_stack_overflow();
return;
}
clear_C1();
if (st0_tag == TAG_Valid) {
long e;
push();
sign = getsign(st1_ptr);
reg_copy(st1_ptr, st_new_ptr);
setexponent16(st_new_ptr, exponent(st_new_ptr));
denormal_arg:
e = exponent16(st_new_ptr);
convert_l2reg(&e, 1);
setexponentpos(st_new_ptr, 0);
setsign(st_new_ptr, sign);
FPU_settag0(TAG_Valid);
return;
} else if (st0_tag == TAG_Zero) {
sign = getsign(st0_ptr);
if (FPU_divide_by_zero(0, SIGN_NEG) < 0)
return;
push();
FPU_copy_to_reg0(&CONST_Z, TAG_Zero);
setsign(st_new_ptr, sign);
return;
}
if (st0_tag == TAG_Special)
st0_tag = FPU_Special(st0_ptr);
if (st0_tag == TW_Denormal) {
if (denormal_operand() < 0)
return;
push();
sign = getsign(st1_ptr);
FPU_to_exp16(st1_ptr, st_new_ptr);
goto denormal_arg;
} else if (st0_tag == TW_Infinity) {
sign = getsign(st0_ptr);
setpositive(st0_ptr);
push();
FPU_copy_to_reg0(&CONST_INF, TAG_Special);
setsign(st_new_ptr, sign);
return;
} else if (st0_tag == TW_NaN) {
if (real_1op_NaN(st0_ptr) < 0)
return;
push();
FPU_copy_to_reg0(st0_ptr, TAG_Special);
return;
} else if (st0_tag == TAG_Empty) {
if (control_word & EX_Invalid) {
FPU_stack_underflow();
push();
FPU_stack_underflow();
} else
EXCEPTION(EX_StackUnder);
}
#ifdef PARANOID
else
EXCEPTION(EX_INTERNAL | 0x119);
#endif
}
int FPU_div(int flags, int rm, int control_w)
{
FPU_REG x, y;
FPU_REG const *a, *b, *st0_ptr, *st_ptr;
FPU_REG *dest;
u_char taga, tagb, signa, signb, sign, saved_sign;
int tag, deststnr;
if (flags & DEST_RM)
deststnr = rm;
else
deststnr = 0;
if (flags & REV) {
b = &st(0);
st0_ptr = b;
tagb = FPU_gettag0();
if (flags & LOADED) {
a = (FPU_REG *) rm;
taga = flags & 0x0f;
} else {
a = &st(rm);
st_ptr = a;
taga = FPU_gettagi(rm);
}
} else {
a = &st(0);
st0_ptr = a;
taga = FPU_gettag0();
if (flags & LOADED) {
b = (FPU_REG *) rm;
tagb = flags & 0x0f;
} else {
b = &st(rm);
st_ptr = b;
tagb = FPU_gettagi(rm);
}
}
signa = getsign(a);
signb = getsign(b);
sign = signa ^ signb;
dest = &st(deststnr);
saved_sign = getsign(dest);
if (!(taga | tagb)) {
reg_copy(a, &x);
reg_copy(b, &y);
setpositive(&x);
setpositive(&y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
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_Valid) && (tagb == TW_Denormal))
|| ((taga == TW_Denormal) && (tagb == TAG_Valid))
|| ((taga == TW_Denormal) && (tagb == TW_Denormal))) {
if (denormal_operand() < 0)
return FPU_Exception;
FPU_to_exp16(a, &x);
FPU_to_exp16(b, &y);
tag = FPU_u_div(&x, &y, dest, control_w, sign);
if (tag < 0)
return tag;
FPU_settagi(deststnr, tag);
return tag;
} else if ((taga <= TW_Denormal) && (tagb <= TW_Denormal)) {
if (tagb != TAG_Zero) {
if (tagb == TW_Denormal) {
if (denormal_operand() < 0)
return FPU_Exception;
}
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
if (taga == TAG_Zero) {
return arith_invalid(deststnr);
}
return FPU_divide_by_zero(deststnr, sign);
}
else if ((taga == TW_NaN) || (tagb == TW_NaN)) {
if (flags & LOADED)
return real_2op_NaN((FPU_REG *) rm, flags & 0x0f, 0,
st0_ptr);
if (flags & DEST_RM) {
int tag;
tag = FPU_gettag0();
if (tag == TAG_Special)
tag = FPU_Special(st0_ptr);
return real_2op_NaN(st0_ptr, tag, rm,
(flags & REV) ? st0_ptr : &st(rm));
} else {
int tag;
tag = FPU_gettagi(rm);
if (tag == TAG_Special)
tag = FPU_Special(&st(rm));
return real_2op_NaN(&st(rm), tag, 0,
(flags & REV) ? st0_ptr : &st(rm));
}
} else if (taga == TW_Infinity) {
if (tagb == TW_Infinity) {
return arith_invalid(deststnr);
} else {
if ((tagb == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
FPU_copy_to_regi(a, TAG_Special, deststnr);
setsign(dest, sign);
return taga;
}
} else if (tagb == TW_Infinity) {
if ((taga == TW_Denormal) && (denormal_operand() < 0))
return FPU_Exception;
FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
setsign(dest, sign);
return TAG_Zero;
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x102);
return FPU_Exception;
}
#endif
return 0;
}
