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 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 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);
}
