Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
diff --git a/arch/i386/math-emu/fpu_trig.c b/arch/i386/math-emu/fpu_trig.c
new file mode 100644
index 0000000..403cbde
--- /dev/null
+++ b/arch/i386/math-emu/fpu_trig.c
@@ -0,0 +1,1845 @@
+/*---------------------------------------------------------------------------+
+ | fpu_trig.c |
+ | |
+ | Implementation of the FPU "transcendental" functions. |
+ | |
+ | Copyright (C) 1992,1993,1994,1997,1999 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
+ | Australia. E-mail billm@melbpc.org.au |
+ | |
+ | |
+ +---------------------------------------------------------------------------*/
+
+#include "fpu_system.h"
+#include "exception.h"
+#include "fpu_emu.h"
+#include "status_w.h"
+#include "control_w.h"
+#include "reg_constant.h"
+
+static void rem_kernel(unsigned long long st0, unsigned long long *y,
+ unsigned long long st1,
+ unsigned long long q, int n);
+
+#define BETTER_THAN_486
+
+#define FCOS 4
+
+/* Used only by fptan, fsin, fcos, and fsincos. */
+/* This routine produces very accurate results, similar to
+ using a value of pi with more than 128 bits precision. */
+/* Limited measurements show no results worse than 64 bit precision
+ except for the results for arguments close to 2^63, where the
+ precision of the result sometimes degrades to about 63.9 bits */
+static int trig_arg(FPU_REG *st0_ptr, int even)
+{
+ FPU_REG tmp;
+ u_char tmptag;
+ unsigned long long q;
+ int old_cw = control_word, saved_status = partial_status;
+ int tag, st0_tag = TAG_Valid;
+
+ if ( exponent(st0_ptr) >= 63 )
+ {
+ partial_status |= SW_C2; /* Reduction incomplete. */
+ return -1;
+ }
+
+ control_word &= ~CW_RC;
+ control_word |= RC_CHOP;
+
+ setpositive(st0_ptr);
+ tag = FPU_u_div(st0_ptr, &CONST_PI2, &tmp, PR_64_BITS | RC_CHOP | 0x3f,
+ SIGN_POS);
+
+ FPU_round_to_int(&tmp, tag); /* Fortunately, this can't overflow
+ to 2^64 */
+ q = significand(&tmp);
+ if ( q )
+ {
+ rem_kernel(significand(st0_ptr),
+ &significand(&tmp),
+ significand(&CONST_PI2),
+ q, exponent(st0_ptr) - exponent(&CONST_PI2));
+ setexponent16(&tmp, exponent(&CONST_PI2));
+ st0_tag = FPU_normalize(&tmp);
+ FPU_copy_to_reg0(&tmp, st0_tag);
+ }
+
+ if ( (even && !(q & 1)) || (!even && (q & 1)) )
+ {
+ st0_tag = FPU_sub(REV|LOADED|TAG_Valid, (int)&CONST_PI2, FULL_PRECISION);
+
+#ifdef BETTER_THAN_486
+ /* So far, the results are exact but based upon a 64 bit
+ precision approximation to pi/2. The technique used
+ now is equivalent to using an approximation to pi/2 which
+ is accurate to about 128 bits. */
+ if ( (exponent(st0_ptr) <= exponent(&CONST_PI2extra) + 64) || (q > 1) )
+ {
+ /* This code gives the effect of having pi/2 to better than
+ 128 bits precision. */
+
+ significand(&tmp) = q + 1;
+ setexponent16(&tmp, 63);
+ FPU_normalize(&tmp);
+ tmptag =
+ FPU_u_mul(&CONST_PI2extra, &tmp, &tmp, FULL_PRECISION, SIGN_POS,
+ exponent(&CONST_PI2extra) + exponent(&tmp));
+ setsign(&tmp, getsign(&CONST_PI2extra));
+ st0_tag = FPU_add(&tmp, tmptag, 0, FULL_PRECISION);
+ if ( signnegative(st0_ptr) )
+ {
+ /* CONST_PI2extra is negative, so the result of the addition
+ can be negative. This means that the argument is actually
+ in a different quadrant. The correction is always < pi/2,
+ so it can't overflow into yet another quadrant. */
+ setpositive(st0_ptr);
+ q++;
+ }
+ }
+#endif /* BETTER_THAN_486 */
+ }
+#ifdef BETTER_THAN_486
+ else
+ {
+ /* So far, the results are exact but based upon a 64 bit
+ precision approximation to pi/2. The technique used
+ now is equivalent to using an approximation to pi/2 which
+ is accurate to about 128 bits. */
+ if ( ((q > 0) && (exponent(st0_ptr) <= exponent(&CONST_PI2extra) + 64))
+ || (q > 1) )
+ {
+ /* This code gives the effect of having p/2 to better than
+ 128 bits precision. */
+
+ significand(&tmp) = q;
+ setexponent16(&tmp, 63);
+ FPU_normalize(&tmp); /* This must return TAG_Valid */
+ tmptag = FPU_u_mul(&CONST_PI2extra, &tmp, &tmp, FULL_PRECISION,
+ SIGN_POS,
+ exponent(&CONST_PI2extra) + exponent(&tmp));
+ setsign(&tmp, getsign(&CONST_PI2extra));
+ st0_tag = FPU_sub(LOADED|(tmptag & 0x0f), (int)&tmp,
+ FULL_PRECISION);
+ if ( (exponent(st0_ptr) == exponent(&CONST_PI2)) &&
+ ((st0_ptr->sigh > CONST_PI2.sigh)
+ || ((st0_ptr->sigh == CONST_PI2.sigh)
+ && (st0_ptr->sigl > CONST_PI2.sigl))) )
+ {
+ /* CONST_PI2extra is negative, so the result of the
+ subtraction can be larger than pi/2. This means
+ that the argument is actually in a different quadrant.
+ The correction is always < pi/2, so it can't overflow
+ into yet another quadrant. */
+ st0_tag = FPU_sub(REV|LOADED|TAG_Valid, (int)&CONST_PI2,
+ FULL_PRECISION);
+ q++;
+ }
+ }
+ }
+#endif /* BETTER_THAN_486 */
+
+ FPU_settag0(st0_tag);
+ control_word = old_cw;
+ partial_status = saved_status & ~SW_C2; /* Reduction complete. */
+
+ return (q & 3) | even;
+}
+
+
+/* Convert a long to register */
+static void convert_l2reg(long const *arg, int deststnr)
+{
+ int tag;
+ long num = *arg;
+ u_char sign;
+ FPU_REG *dest = &st(deststnr);
+
+ if (num == 0)
+ {
+ FPU_copy_to_regi(&CONST_Z, TAG_Zero, deststnr);
+ return;
+ }
+
+ if (num > 0)
+ { sign = SIGN_POS; }
+ else
+ { num = -num; sign = SIGN_NEG; }
+
+ dest->sigh = num;
+ dest->sigl = 0;
+ setexponent16(dest, 31);
+ tag = FPU_normalize(dest);
+ FPU_settagi(deststnr, tag);
+ setsign(dest, sign);
+ return;
+}
+
+
+static void single_arg_error(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ if ( st0_tag == TAG_Empty )
+ FPU_stack_underflow(); /* Puts a QNaN in st(0) */
+ else if ( st0_tag == TW_NaN )
+ real_1op_NaN(st0_ptr); /* return with a NaN in st(0) */
+#ifdef PARANOID
+ else
+ EXCEPTION(EX_INTERNAL|0x0112);
+#endif /* PARANOID */
+}
+
+
+static void single_arg_2_error(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ int isNaN;
+
+ switch ( st0_tag )
+ {
+ case TW_NaN:
+ isNaN = (exponent(st0_ptr) == EXP_OVER) && (st0_ptr->sigh & 0x80000000);
+ if ( isNaN && !(st0_ptr->sigh & 0x40000000) ) /* Signaling ? */
+ {
+ EXCEPTION(EX_Invalid);
+ if ( control_word & CW_Invalid )
+ {
+ /* The masked response */
+ /* Convert to a QNaN */
+ st0_ptr->sigh |= 0x40000000;
+ push();
+ FPU_copy_to_reg0(st0_ptr, TAG_Special);
+ }
+ }
+ else if ( isNaN )
+ {
+ /* A QNaN */
+ push();
+ FPU_copy_to_reg0(st0_ptr, TAG_Special);
+ }
+ else
+ {
+ /* pseudoNaN or other unsupported */
+ EXCEPTION(EX_Invalid);
+ if ( control_word & CW_Invalid )
+ {
+ /* The masked response */
+ FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
+ push();
+ FPU_copy_to_reg0(&CONST_QNaN, TAG_Special);
+ }
+ }
+ break; /* return with a NaN in st(0) */
+#ifdef PARANOID
+ default:
+ EXCEPTION(EX_INTERNAL|0x0112);
+#endif /* PARANOID */
+ }
+}
+
+
+/*---------------------------------------------------------------------------*/
+
+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 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);
+}
+
+
+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; /* anticipate */
+
+ 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); /* Needed if arg was a denormal */
+ 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 )
+ {
+ /* Is this the correct behaviour? */
+ if ( control_word & EX_Invalid )
+ {
+ FPU_stack_underflow();
+ push();
+ FPU_stack_underflow();
+ }
+ else
+ EXCEPTION(EX_StackUnder);
+ }
+#ifdef PARANOID
+ else
+ EXCEPTION(EX_INTERNAL | 0x119);
+#endif /* PARANOID */
+}
+
+
+static void fdecstp(void)
+{
+ clear_C1();
+ top--;
+}
+
+static void fincstp(void)
+{
+ clear_C1();
+ top++;
+}
+
+
+static void fsqrt_(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ int expon;
+
+ clear_C1();
+
+ if ( st0_tag == TAG_Valid )
+ {
+ u_char tag;
+
+ if (signnegative(st0_ptr))
+ {
+ arith_invalid(0); /* sqrt(negative) is invalid */
+ return;
+ }
+
+ /* make st(0) in [1.0 .. 4.0) */
+ expon = exponent(st0_ptr);
+
+ denormal_arg:
+
+ setexponent16(st0_ptr, (expon & 1));
+
+ /* Do the computation, the sign of the result will be positive. */
+ tag = wm_sqrt(st0_ptr, 0, 0, control_word, SIGN_POS);
+ addexponent(st0_ptr, expon >> 1);
+ FPU_settag0(tag);
+ return;
+ }
+
+ if ( st0_tag == TAG_Zero )
+ return;
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+
+ if ( st0_tag == TW_Infinity )
+ {
+ if ( signnegative(st0_ptr) )
+ arith_invalid(0); /* sqrt(-Infinity) is invalid */
+ return;
+ }
+ else if ( st0_tag == TW_Denormal )
+ {
+ if (signnegative(st0_ptr))
+ {
+ arith_invalid(0); /* sqrt(negative) is invalid */
+ return;
+ }
+
+ if ( denormal_operand() < 0 )
+ return;
+
+ FPU_to_exp16(st0_ptr, st0_ptr);
+
+ expon = exponent16(st0_ptr);
+
+ goto denormal_arg;
+ }
+
+ single_arg_error(st0_ptr, st0_tag);
+
+}
+
+
+static void frndint_(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ int flags, tag;
+
+ if ( st0_tag == TAG_Valid )
+ {
+ u_char sign;
+
+ denormal_arg:
+
+ sign = getsign(st0_ptr);
+
+ if (exponent(st0_ptr) > 63)
+ return;
+
+ if ( st0_tag == TW_Denormal )
+ {
+ if (denormal_operand() < 0 )
+ return;
+ }
+
+ /* Fortunately, this can't overflow to 2^64 */
+ if ( (flags = FPU_round_to_int(st0_ptr, st0_tag)) )
+ set_precision_flag(flags);
+
+ setexponent16(st0_ptr, 63);
+ tag = FPU_normalize(st0_ptr);
+ setsign(st0_ptr, sign);
+ FPU_settag0(tag);
+ return;
+ }
+
+ if ( st0_tag == TAG_Zero )
+ return;
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+
+ if ( st0_tag == TW_Denormal )
+ goto denormal_arg;
+ else if ( st0_tag == TW_Infinity )
+ return;
+ else
+ single_arg_error(st0_ptr, st0_tag);
+}
+
+
+static int fsin(FPU_REG *st0_ptr, u_char tag)
+{
+ u_char arg_sign = getsign(st0_ptr);
+
+ if ( tag == TAG_Valid )
+ {
+ int q;
+
+ if ( exponent(st0_ptr) > -40 )
+ {
+ if ( (q = trig_arg(st0_ptr, 0)) == -1 )
+ {
+ /* Operand is out of range */
+ return 1;
+ }
+
+ poly_sine(st0_ptr);
+
+ if (q & 2)
+ changesign(st0_ptr);
+
+ setsign(st0_ptr, getsign(st0_ptr) ^ arg_sign);
+
+ /* We do not really know if up or down */
+ set_precision_flag_up();
+ return 0;
+ }
+ else
+ {
+ /* For a small arg, the result == the argument */
+ set_precision_flag_up(); /* Must be up. */
+ return 0;
+ }
+ }
+
+ if ( tag == TAG_Zero )
+ {
+ setcc(0);
+ return 0;
+ }
+
+ if ( tag == TAG_Special )
+ tag = FPU_Special(st0_ptr);
+
+ if ( tag == TW_Denormal )
+ {
+ if ( denormal_operand() < 0 )
+ return 1;
+
+ /* For a small arg, the result == the argument */
+ /* Underflow may happen */
+ FPU_to_exp16(st0_ptr, st0_ptr);
+
+ tag = FPU_round(st0_ptr, 1, 0, FULL_PRECISION, arg_sign);
+
+ FPU_settag0(tag);
+
+ return 0;
+ }
+ else if ( tag == TW_Infinity )
+ {
+ /* The 80486 treats infinity as an invalid operand */
+ arith_invalid(0);
+ return 1;
+ }
+ else
+ {
+ single_arg_error(st0_ptr, tag);
+ return 1;
+ }
+}
+
+
+static int f_cos(FPU_REG *st0_ptr, u_char tag)
+{
+ u_char st0_sign;
+
+ st0_sign = getsign(st0_ptr);
+
+ if ( tag == TAG_Valid )
+ {
+ int q;
+
+ if ( exponent(st0_ptr) > -40 )
+ {
+ if ( (exponent(st0_ptr) < 0)
+ || ((exponent(st0_ptr) == 0)
+ && (significand(st0_ptr) <= 0xc90fdaa22168c234LL)) )
+ {
+ poly_cos(st0_ptr);
+
+ /* We do not really know if up or down */
+ set_precision_flag_down();
+
+ return 0;
+ }
+ else if ( (q = trig_arg(st0_ptr, FCOS)) != -1 )
+ {
+ poly_sine(st0_ptr);
+
+ if ((q+1) & 2)
+ changesign(st0_ptr);
+
+ /* We do not really know if up or down */
+ set_precision_flag_down();
+
+ return 0;
+ }
+ else
+ {
+ /* Operand is out of range */
+ return 1;
+ }
+ }
+ else
+ {
+ denormal_arg:
+
+ setcc(0);
+ FPU_copy_to_reg0(&CONST_1, TAG_Valid);
+#ifdef PECULIAR_486
+ set_precision_flag_down(); /* 80486 appears to do this. */
+#else
+ set_precision_flag_up(); /* Must be up. */
+#endif /* PECULIAR_486 */
+ return 0;
+ }
+ }
+ else if ( tag == TAG_Zero )
+ {
+ FPU_copy_to_reg0(&CONST_1, TAG_Valid);
+ setcc(0);
+ return 0;
+ }
+
+ if ( tag == TAG_Special )
+ tag = FPU_Special(st0_ptr);
+
+ if ( tag == TW_Denormal )
+ {
+ if ( denormal_operand() < 0 )
+ return 1;
+
+ goto denormal_arg;
+ }
+ else if ( tag == TW_Infinity )
+ {
+ /* The 80486 treats infinity as an invalid operand */
+ arith_invalid(0);
+ return 1;
+ }
+ else
+ {
+ single_arg_error(st0_ptr, tag); /* requires st0_ptr == &st(0) */
+ return 1;
+ }
+}
+
+
+static void fcos(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ f_cos(st0_ptr, st0_tag);
+}
+
+
+static void fsincos(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ FPU_REG *st_new_ptr;
+ FPU_REG arg;
+ u_char tag;
+
+ /* 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_Special )
+ tag = FPU_Special(st0_ptr);
+ else
+ tag = st0_tag;
+
+ if ( tag == TW_NaN )
+ {
+ single_arg_2_error(st0_ptr, TW_NaN);
+ return;
+ }
+ else if ( tag == TW_Infinity )
+ {
+ /* The 80486 treats infinity as an invalid operand */
+ if ( arith_invalid(0) >= 0 )
+ {
+ /* Masked response */
+ push();
+ arith_invalid(0);
+ }
+ return;
+ }
+
+ reg_copy(st0_ptr, &arg);
+ if ( !fsin(st0_ptr, st0_tag) )
+ {
+ push();
+ FPU_copy_to_reg0(&arg, st0_tag);
+ f_cos(&st(0), st0_tag);
+ }
+ else
+ {
+ /* An error, so restore st(0) */
+ FPU_copy_to_reg0(&arg, st0_tag);
+ }
+}
+
+
+/*---------------------------------------------------------------------------*/
+/* The following all require two arguments: st(0) and st(1) */
+
+/* A lean, mean kernel for the fprem instructions. This relies upon
+ the division and rounding to an integer in do_fprem giving an
+ exact result. Because of this, rem_kernel() needs to deal only with
+ the least significant 64 bits, the more significant bits of the
+ result must be zero.
+ */
+static void rem_kernel(unsigned long long st0, unsigned long long *y,
+ unsigned long long st1,
+ unsigned long long q, int n)
+{
+ int dummy;
+ unsigned long long x;
+
+ x = st0 << n;
+
+ /* Do the required multiplication and subtraction in the one operation */
+
+ /* lsw x -= lsw st1 * lsw q */
+ asm volatile ("mull %4; subl %%eax,%0; sbbl %%edx,%1"
+ :"=m" (((unsigned *)&x)[0]), "=m" (((unsigned *)&x)[1]),
+ "=a" (dummy)
+ :"2" (((unsigned *)&st1)[0]), "m" (((unsigned *)&q)[0])
+ :"%dx");
+ /* msw x -= msw st1 * lsw q */
+ asm volatile ("mull %3; subl %%eax,%0"
+ :"=m" (((unsigned *)&x)[1]), "=a" (dummy)
+ :"1" (((unsigned *)&st1)[1]), "m" (((unsigned *)&q)[0])
+ :"%dx");
+ /* msw x -= lsw st1 * msw q */
+ asm volatile ("mull %3; subl %%eax,%0"
+ :"=m" (((unsigned *)&x)[1]), "=a" (dummy)
+ :"1" (((unsigned *)&st1)[0]), "m" (((unsigned *)&q)[1])
+ :"%dx");
+
+ *y = x;
+}
+
+
+/* Remainder of st(0) / st(1) */
+/* This routine produces exact results, i.e. there is never any
+ rounding or truncation, etc of the result. */
+static void do_fprem(FPU_REG *st0_ptr, u_char st0_tag, int round)
+{
+ FPU_REG *st1_ptr = &st(1);
+ u_char st1_tag = FPU_gettagi(1);
+
+ if ( !((st0_tag ^ TAG_Valid) | (st1_tag ^ TAG_Valid)) )
+ {
+ FPU_REG tmp, st0, st1;
+ u_char st0_sign, st1_sign;
+ u_char tmptag;
+ int tag;
+ int old_cw;
+ int expdif;
+ long long q;
+ unsigned short saved_status;
+ int cc;
+
+ fprem_valid:
+ /* Convert registers for internal use. */
+ st0_sign = FPU_to_exp16(st0_ptr, &st0);
+ st1_sign = FPU_to_exp16(st1_ptr, &st1);
+ expdif = exponent16(&st0) - exponent16(&st1);
+
+ old_cw = control_word;
+ cc = 0;
+
+ /* We want the status following the denorm tests, but don't want
+ the status changed by the arithmetic operations. */
+ saved_status = partial_status;
+ control_word &= ~CW_RC;
+ control_word |= RC_CHOP;
+
+ if ( expdif < 64 )
+ {
+ /* This should be the most common case */
+
+ if ( expdif > -2 )
+ {
+ u_char sign = st0_sign ^ st1_sign;
+ tag = FPU_u_div(&st0, &st1, &tmp,
+ PR_64_BITS | RC_CHOP | 0x3f,
+ sign);
+ setsign(&tmp, sign);
+
+ if ( exponent(&tmp) >= 0 )
+ {
+ FPU_round_to_int(&tmp, tag); /* Fortunately, this can't
+ overflow to 2^64 */
+ q = significand(&tmp);
+
+ rem_kernel(significand(&st0),
+ &significand(&tmp),
+ significand(&st1),
+ q, expdif);
+
+ setexponent16(&tmp, exponent16(&st1));
+ }
+ else
+ {
+ reg_copy(&st0, &tmp);
+ q = 0;
+ }
+
+ if ( (round == RC_RND) && (tmp.sigh & 0xc0000000) )
+ {
+ /* We may need to subtract st(1) once more,
+ to get a result <= 1/2 of st(1). */
+ unsigned long long x;
+ expdif = exponent16(&st1) - exponent16(&tmp);
+ if ( expdif <= 1 )
+ {
+ if ( expdif == 0 )
+ x = significand(&st1) - significand(&tmp);
+ else /* expdif is 1 */
+ x = (significand(&st1) << 1) - significand(&tmp);
+ if ( (x < significand(&tmp)) ||
+ /* or equi-distant (from 0 & st(1)) and q is odd */
+ ((x == significand(&tmp)) && (q & 1) ) )
+ {
+ st0_sign = ! st0_sign;
+ significand(&tmp) = x;
+ q++;
+ }
+ }
+ }
+
+ if (q & 4) cc |= SW_C0;
+ if (q & 2) cc |= SW_C3;
+ if (q & 1) cc |= SW_C1;
+ }
+ else
+ {
+ control_word = old_cw;
+ setcc(0);
+ return;
+ }
+ }
+ else
+ {
+ /* There is a large exponent difference ( >= 64 ) */
+ /* To make much sense, the code in this section should
+ be done at high precision. */
+ int exp_1, N;
+ u_char sign;
+
+ /* prevent overflow here */
+ /* N is 'a number between 32 and 63' (p26-113) */
+ reg_copy(&st0, &tmp);
+ tmptag = st0_tag;
+ N = (expdif & 0x0000001f) + 32; /* This choice gives results
+ identical to an AMD 486 */
+ setexponent16(&tmp, N);
+ exp_1 = exponent16(&st1);
+ setexponent16(&st1, 0);
+ expdif -= N;
+
+ sign = getsign(&tmp) ^ st1_sign;
+ tag = FPU_u_div(&tmp, &st1, &tmp, PR_64_BITS | RC_CHOP | 0x3f,
+ sign);
+ setsign(&tmp, sign);
+
+ FPU_round_to_int(&tmp, tag); /* Fortunately, this can't
+ overflow to 2^64 */
+
+ rem_kernel(significand(&st0),
+ &significand(&tmp),
+ significand(&st1),
+ significand(&tmp),
+ exponent(&tmp)
+ );
+ setexponent16(&tmp, exp_1 + expdif);
+
+ /* It is possible for the operation to be complete here.
+ What does the IEEE standard say? The Intel 80486 manual
+ implies that the operation will never be completed at this
+ point, and the behaviour of a real 80486 confirms this.
+ */
+ if ( !(tmp.sigh | tmp.sigl) )
+ {
+ /* The result is zero */
+ control_word = old_cw;
+ partial_status = saved_status;
+ FPU_copy_to_reg0(&CONST_Z, TAG_Zero);
+ setsign(&st0, st0_sign);
+#ifdef PECULIAR_486
+ setcc(SW_C2);
+#else
+ setcc(0);
+#endif /* PECULIAR_486 */
+ return;
+ }
+ cc = SW_C2;
+ }
+
+ control_word = old_cw;
+ partial_status = saved_status;
+ tag = FPU_normalize_nuo(&tmp);
+ reg_copy(&tmp, st0_ptr);
+
+ /* The only condition to be looked for is underflow,
+ and it can occur here only if underflow is unmasked. */
+ if ( (exponent16(&tmp) <= EXP_UNDER) && (tag != TAG_Zero)
+ && !(control_word & CW_Underflow) )
+ {
+ setcc(cc);
+ tag = arith_underflow(st0_ptr);
+ setsign(st0_ptr, st0_sign);
+ FPU_settag0(tag);
+ return;
+ }
+ else if ( (exponent16(&tmp) > EXP_UNDER) || (tag == TAG_Zero) )
+ {
+ stdexp(st0_ptr);
+ setsign(st0_ptr, st0_sign);
+ }
+ else
+ {
+ tag = FPU_round(st0_ptr, 0, 0, FULL_PRECISION, st0_sign);
+ }
+ FPU_settag0(tag);
+ setcc(cc);
+
+ return;
+ }
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+ if ( st1_tag == TAG_Special )
+ st1_tag = FPU_Special(st1_ptr);
+
+ if ( ((st0_tag == TAG_Valid) && (st1_tag == TW_Denormal))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TAG_Valid))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TW_Denormal)) )
+ {
+ if ( denormal_operand() < 0 )
+ return;
+ goto fprem_valid;
+ }
+ else if ( (st0_tag == TAG_Empty) || (st1_tag == TAG_Empty) )
+ {
+ FPU_stack_underflow();
+ return;
+ }
+ else if ( st0_tag == TAG_Zero )
+ {
+ if ( st1_tag == TAG_Valid )
+ {
+ setcc(0); return;
+ }
+ else if ( st1_tag == TW_Denormal )
+ {
+ if ( denormal_operand() < 0 )
+ return;
+ setcc(0); return;
+ }
+ else if ( st1_tag == TAG_Zero )
+ { arith_invalid(0); return; } /* fprem(?,0) always invalid */
+ else if ( st1_tag == TW_Infinity )
+ { setcc(0); return; }
+ }
+ else if ( (st0_tag == TAG_Valid) || (st0_tag == TW_Denormal) )
+ {
+ if ( st1_tag == TAG_Zero )
+ {
+ arith_invalid(0); /* fprem(Valid,Zero) is invalid */
+ return;
+ }
+ else if ( st1_tag != TW_NaN )
+ {
+ if ( ((st0_tag == TW_Denormal) || (st1_tag == TW_Denormal))
+ && (denormal_operand() < 0) )
+ return;
+
+ if ( st1_tag == TW_Infinity )
+ {
+ /* fprem(Valid,Infinity) is o.k. */
+ setcc(0); return;
+ }
+ }
+ }
+ else if ( st0_tag == TW_Infinity )
+ {
+ if ( st1_tag != TW_NaN )
+ {
+ arith_invalid(0); /* fprem(Infinity,?) is invalid */
+ return;
+ }
+ }
+
+ /* One of the registers must contain a NaN if we got here. */
+
+#ifdef PARANOID
+ if ( (st0_tag != TW_NaN) && (st1_tag != TW_NaN) )
+ EXCEPTION(EX_INTERNAL | 0x118);
+#endif /* PARANOID */
+
+ real_2op_NaN(st1_ptr, st1_tag, 0, st1_ptr);
+
+}
+
+
+/* ST(1) <- ST(1) * log ST; pop ST */
+static void fyl2x(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ FPU_REG *st1_ptr = &st(1), exponent;
+ u_char st1_tag = FPU_gettagi(1);
+ u_char sign;
+ int e, tag;
+
+ clear_C1();
+
+ if ( (st0_tag == TAG_Valid) && (st1_tag == TAG_Valid) )
+ {
+ both_valid:
+ /* Both regs are Valid or Denormal */
+ if ( signpositive(st0_ptr) )
+ {
+ if ( st0_tag == TW_Denormal )
+ FPU_to_exp16(st0_ptr, st0_ptr);
+ else
+ /* Convert st(0) for internal use. */
+ setexponent16(st0_ptr, exponent(st0_ptr));
+
+ if ( (st0_ptr->sigh == 0x80000000) && (st0_ptr->sigl == 0) )
+ {
+ /* Special case. The result can be precise. */
+ u_char esign;
+ e = exponent16(st0_ptr);
+ if ( e >= 0 )
+ {
+ exponent.sigh = e;
+ esign = SIGN_POS;
+ }
+ else
+ {
+ exponent.sigh = -e;
+ esign = SIGN_NEG;
+ }
+ exponent.sigl = 0;
+ setexponent16(&exponent, 31);
+ tag = FPU_normalize_nuo(&exponent);
+ stdexp(&exponent);
+ setsign(&exponent, esign);
+ tag = FPU_mul(&exponent, tag, 1, FULL_PRECISION);
+ if ( tag >= 0 )
+ FPU_settagi(1, tag);
+ }
+ else
+ {
+ /* The usual case */
+ sign = getsign(st1_ptr);
+ if ( st1_tag == TW_Denormal )
+ FPU_to_exp16(st1_ptr, st1_ptr);
+ else
+ /* Convert st(1) for internal use. */
+ setexponent16(st1_ptr, exponent(st1_ptr));
+ poly_l2(st0_ptr, st1_ptr, sign);
+ }
+ }
+ else
+ {
+ /* negative */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+
+ FPU_pop();
+
+ return;
+ }
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+ if ( st1_tag == TAG_Special )
+ st1_tag = FPU_Special(st1_ptr);
+
+ if ( (st0_tag == TAG_Empty) || (st1_tag == TAG_Empty) )
+ {
+ FPU_stack_underflow_pop(1);
+ return;
+ }
+ else if ( (st0_tag <= TW_Denormal) && (st1_tag <= TW_Denormal) )
+ {
+ if ( st0_tag == TAG_Zero )
+ {
+ if ( st1_tag == TAG_Zero )
+ {
+ /* Both args zero is invalid */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+ else
+ {
+ u_char sign;
+ sign = getsign(st1_ptr)^SIGN_NEG;
+ if ( FPU_divide_by_zero(1, sign) < 0 )
+ return;
+
+ setsign(st1_ptr, sign);
+ }
+ }
+ else if ( st1_tag == TAG_Zero )
+ {
+ /* st(1) contains zero, st(0) valid <> 0 */
+ /* Zero is the valid answer */
+ sign = getsign(st1_ptr);
+
+ if ( signnegative(st0_ptr) )
+ {
+ /* log(negative) */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+ else if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+ else
+ {
+ if ( exponent(st0_ptr) < 0 )
+ sign ^= SIGN_NEG;
+
+ FPU_copy_to_reg1(&CONST_Z, TAG_Zero);
+ setsign(st1_ptr, sign);
+ }
+ }
+ else
+ {
+ /* One or both operands are denormals. */
+ if ( denormal_operand() < 0 )
+ return;
+ goto both_valid;
+ }
+ }
+ else if ( (st0_tag == TW_NaN) || (st1_tag == TW_NaN) )
+ {
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) < 0 )
+ return;
+ }
+ /* One or both arg must be an infinity */
+ else if ( st0_tag == TW_Infinity )
+ {
+ if ( (signnegative(st0_ptr)) || (st1_tag == TAG_Zero) )
+ {
+ /* log(-infinity) or 0*log(infinity) */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+ else
+ {
+ u_char sign = getsign(st1_ptr);
+
+ if ( (st1_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ FPU_copy_to_reg1(&CONST_INF, TAG_Special);
+ setsign(st1_ptr, sign);
+ }
+ }
+ /* st(1) must be infinity here */
+ else if ( ((st0_tag == TAG_Valid) || (st0_tag == TW_Denormal))
+ && ( signpositive(st0_ptr) ) )
+ {
+ if ( exponent(st0_ptr) >= 0 )
+ {
+ if ( (exponent(st0_ptr) == 0) &&
+ (st0_ptr->sigh == 0x80000000) &&
+ (st0_ptr->sigl == 0) )
+ {
+ /* st(0) holds 1.0 */
+ /* infinity*log(1) */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+ /* else st(0) is positive and > 1.0 */
+ }
+ else
+ {
+ /* st(0) is positive and < 1.0 */
+
+ if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ changesign(st1_ptr);
+ }
+ }
+ else
+ {
+ /* st(0) must be zero or negative */
+ if ( st0_tag == TAG_Zero )
+ {
+ /* This should be invalid, but a real 80486 is happy with it. */
+
+#ifndef PECULIAR_486
+ sign = getsign(st1_ptr);
+ if ( FPU_divide_by_zero(1, sign) < 0 )
+ return;
+#endif /* PECULIAR_486 */
+
+ changesign(st1_ptr);
+ }
+ else if ( arith_invalid(1) < 0 ) /* log(negative) */
+ return;
+ }
+
+ FPU_pop();
+}
+
+
+static void fpatan(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ FPU_REG *st1_ptr = &st(1);
+ u_char st1_tag = FPU_gettagi(1);
+ int tag;
+
+ clear_C1();
+ if ( !((st0_tag ^ TAG_Valid) | (st1_tag ^ TAG_Valid)) )
+ {
+ valid_atan:
+
+ poly_atan(st0_ptr, st0_tag, st1_ptr, st1_tag);
+
+ FPU_pop();
+
+ return;
+ }
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+ if ( st1_tag == TAG_Special )
+ st1_tag = FPU_Special(st1_ptr);
+
+ if ( ((st0_tag == TAG_Valid) && (st1_tag == TW_Denormal))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TAG_Valid))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TW_Denormal)) )
+ {
+ if ( denormal_operand() < 0 )
+ return;
+
+ goto valid_atan;
+ }
+ else if ( (st0_tag == TAG_Empty) || (st1_tag == TAG_Empty) )
+ {
+ FPU_stack_underflow_pop(1);
+ return;
+ }
+ else if ( (st0_tag == TW_NaN) || (st1_tag == TW_NaN) )
+ {
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) >= 0 )
+ FPU_pop();
+ return;
+ }
+ else if ( (st0_tag == TW_Infinity) || (st1_tag == TW_Infinity) )
+ {
+ u_char sign = getsign(st1_ptr);
+ if ( st0_tag == TW_Infinity )
+ {
+ if ( st1_tag == TW_Infinity )
+ {
+ if ( signpositive(st0_ptr) )
+ {
+ FPU_copy_to_reg1(&CONST_PI4, TAG_Valid);
+ }
+ else
+ {
+ setpositive(st1_ptr);
+ tag = FPU_u_add(&CONST_PI4, &CONST_PI2, st1_ptr,
+ FULL_PRECISION, SIGN_POS,
+ exponent(&CONST_PI4), exponent(&CONST_PI2));
+ if ( tag >= 0 )
+ FPU_settagi(1, tag);
+ }
+ }
+ else
+ {
+ if ( (st1_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ if ( signpositive(st0_ptr) )
+ {
+ FPU_copy_to_reg1(&CONST_Z, TAG_Zero);
+ setsign(st1_ptr, sign); /* An 80486 preserves the sign */
+ FPU_pop();
+ return;
+ }
+ else
+ {
+ FPU_copy_to_reg1(&CONST_PI, TAG_Valid);
+ }
+ }
+ }
+ else
+ {
+ /* st(1) is infinity, st(0) not infinity */
+ if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ FPU_copy_to_reg1(&CONST_PI2, TAG_Valid);
+ }
+ setsign(st1_ptr, sign);
+ }
+ else if ( st1_tag == TAG_Zero )
+ {
+ /* st(0) must be valid or zero */
+ u_char sign = getsign(st1_ptr);
+
+ if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ if ( signpositive(st0_ptr) )
+ {
+ /* An 80486 preserves the sign */
+ FPU_pop();
+ return;
+ }
+
+ FPU_copy_to_reg1(&CONST_PI, TAG_Valid);
+ setsign(st1_ptr, sign);
+ }
+ else if ( st0_tag == TAG_Zero )
+ {
+ /* st(1) must be TAG_Valid here */
+ u_char sign = getsign(st1_ptr);
+
+ if ( (st1_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ FPU_copy_to_reg1(&CONST_PI2, TAG_Valid);
+ setsign(st1_ptr, sign);
+ }
+#ifdef PARANOID
+ else
+ EXCEPTION(EX_INTERNAL | 0x125);
+#endif /* PARANOID */
+
+ FPU_pop();
+ set_precision_flag_up(); /* We do not really know if up or down */
+}
+
+
+static void fprem(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ do_fprem(st0_ptr, st0_tag, RC_CHOP);
+}
+
+
+static void fprem1(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ do_fprem(st0_ptr, st0_tag, RC_RND);
+}
+
+
+static void fyl2xp1(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ u_char sign, sign1;
+ FPU_REG *st1_ptr = &st(1), a, b;
+ u_char st1_tag = FPU_gettagi(1);
+
+ clear_C1();
+ if ( !((st0_tag ^ TAG_Valid) | (st1_tag ^ TAG_Valid)) )
+ {
+ valid_yl2xp1:
+
+ sign = getsign(st0_ptr);
+ sign1 = getsign(st1_ptr);
+
+ FPU_to_exp16(st0_ptr, &a);
+ FPU_to_exp16(st1_ptr, &b);
+
+ if ( poly_l2p1(sign, sign1, &a, &b, st1_ptr) )
+ return;
+
+ FPU_pop();
+ return;
+ }
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+ if ( st1_tag == TAG_Special )
+ st1_tag = FPU_Special(st1_ptr);
+
+ if ( ((st0_tag == TAG_Valid) && (st1_tag == TW_Denormal))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TAG_Valid))
+ || ((st0_tag == TW_Denormal) && (st1_tag == TW_Denormal)) )
+ {
+ if ( denormal_operand() < 0 )
+ return;
+
+ goto valid_yl2xp1;
+ }
+ else if ( (st0_tag == TAG_Empty) | (st1_tag == TAG_Empty) )
+ {
+ FPU_stack_underflow_pop(1);
+ return;
+ }
+ else if ( st0_tag == TAG_Zero )
+ {
+ switch ( st1_tag )
+ {
+ case TW_Denormal:
+ if ( denormal_operand() < 0 )
+ return;
+
+ case TAG_Zero:
+ case TAG_Valid:
+ setsign(st0_ptr, getsign(st0_ptr) ^ getsign(st1_ptr));
+ FPU_copy_to_reg1(st0_ptr, st0_tag);
+ break;
+
+ case TW_Infinity:
+ /* Infinity*log(1) */
+ if ( arith_invalid(1) < 0 )
+ return;
+ break;
+
+ case TW_NaN:
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) < 0 )
+ return;
+ break;
+
+ default:
+#ifdef PARANOID
+ EXCEPTION(EX_INTERNAL | 0x116);
+ return;
+#endif /* PARANOID */
+ break;
+ }
+ }
+ else if ( (st0_tag == TAG_Valid) || (st0_tag == TW_Denormal) )
+ {
+ switch ( st1_tag )
+ {
+ case TAG_Zero:
+ if ( signnegative(st0_ptr) )
+ {
+ if ( exponent(st0_ptr) >= 0 )
+ {
+ /* st(0) holds <= -1.0 */
+#ifdef PECULIAR_486 /* Stupid 80486 doesn't worry about log(negative). */
+ changesign(st1_ptr);
+#else
+ if ( arith_invalid(1) < 0 )
+ return;
+#endif /* PECULIAR_486 */
+ }
+ else if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+ else
+ changesign(st1_ptr);
+ }
+ else if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+ break;
+
+ case TW_Infinity:
+ if ( signnegative(st0_ptr) )
+ {
+ if ( (exponent(st0_ptr) >= 0) &&
+ !((st0_ptr->sigh == 0x80000000) &&
+ (st0_ptr->sigl == 0)) )
+ {
+ /* st(0) holds < -1.0 */
+#ifdef PECULIAR_486 /* Stupid 80486 doesn't worry about log(negative). */
+ changesign(st1_ptr);
+#else
+ if ( arith_invalid(1) < 0 ) return;
+#endif /* PECULIAR_486 */
+ }
+ else if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+ else
+ changesign(st1_ptr);
+ }
+ else if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+ break;
+
+ case TW_NaN:
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) < 0 )
+ return;
+ }
+
+ }
+ else if ( st0_tag == TW_NaN )
+ {
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) < 0 )
+ return;
+ }
+ else if ( st0_tag == TW_Infinity )
+ {
+ if ( st1_tag == TW_NaN )
+ {
+ if ( real_2op_NaN(st0_ptr, st0_tag, 1, st0_ptr) < 0 )
+ return;
+ }
+ else if ( signnegative(st0_ptr) )
+ {
+#ifndef PECULIAR_486
+ /* This should have higher priority than denormals, but... */
+ if ( arith_invalid(1) < 0 ) /* log(-infinity) */
+ return;
+#endif /* PECULIAR_486 */
+ if ( (st1_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+#ifdef PECULIAR_486
+ /* Denormal operands actually get higher priority */
+ if ( arith_invalid(1) < 0 ) /* log(-infinity) */
+ return;
+#endif /* PECULIAR_486 */
+ }
+ else if ( st1_tag == TAG_Zero )
+ {
+ /* log(infinity) */
+ if ( arith_invalid(1) < 0 )
+ return;
+ }
+
+ /* st(1) must be valid here. */
+
+ else if ( (st1_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ /* The Manual says that log(Infinity) is invalid, but a real
+ 80486 sensibly says that it is o.k. */
+ else
+ {
+ u_char sign = getsign(st1_ptr);
+ FPU_copy_to_reg1(&CONST_INF, TAG_Special);
+ setsign(st1_ptr, sign);
+ }
+ }
+#ifdef PARANOID
+ else
+ {
+ EXCEPTION(EX_INTERNAL | 0x117);
+ return;
+ }
+#endif /* PARANOID */
+
+ FPU_pop();
+ return;
+
+}
+
+
+static void fscale(FPU_REG *st0_ptr, u_char st0_tag)
+{
+ FPU_REG *st1_ptr = &st(1);
+ u_char st1_tag = FPU_gettagi(1);
+ int old_cw = control_word;
+ u_char sign = getsign(st0_ptr);
+
+ clear_C1();
+ if ( !((st0_tag ^ TAG_Valid) | (st1_tag ^ TAG_Valid)) )
+ {
+ long scale;
+ FPU_REG tmp;
+
+ /* Convert register for internal use. */
+ setexponent16(st0_ptr, exponent(st0_ptr));
+
+ valid_scale:
+
+ if ( exponent(st1_ptr) > 30 )
+ {
+ /* 2^31 is far too large, would require 2^(2^30) or 2^(-2^30) */
+
+ if ( signpositive(st1_ptr) )
+ {
+ EXCEPTION(EX_Overflow);
+ FPU_copy_to_reg0(&CONST_INF, TAG_Special);
+ }
+ else
+ {
+ EXCEPTION(EX_Underflow);
+ FPU_copy_to_reg0(&CONST_Z, TAG_Zero);
+ }
+ setsign(st0_ptr, sign);
+ return;
+ }
+
+ control_word &= ~CW_RC;
+ control_word |= RC_CHOP;
+ reg_copy(st1_ptr, &tmp);
+ FPU_round_to_int(&tmp, st1_tag); /* This can never overflow here */
+ control_word = old_cw;
+ scale = signnegative(st1_ptr) ? -tmp.sigl : tmp.sigl;
+ scale += exponent16(st0_ptr);
+
+ setexponent16(st0_ptr, scale);
+
+ /* Use FPU_round() to properly detect under/overflow etc */
+ FPU_round(st0_ptr, 0, 0, control_word, sign);
+
+ return;
+ }
+
+ if ( st0_tag == TAG_Special )
+ st0_tag = FPU_Special(st0_ptr);
+ if ( st1_tag == TAG_Special )
+ st1_tag = FPU_Special(st1_ptr);
+
+ if ( (st0_tag == TAG_Valid) || (st0_tag == TW_Denormal) )
+ {
+ switch ( st1_tag )
+ {
+ case TAG_Valid:
+ /* st(0) must be a denormal */
+ if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ FPU_to_exp16(st0_ptr, st0_ptr); /* Will not be left on stack */
+ goto valid_scale;
+
+ case TAG_Zero:
+ if ( st0_tag == TW_Denormal )
+ denormal_operand();
+ return;
+
+ case TW_Denormal:
+ denormal_operand();
+ return;
+
+ case TW_Infinity:
+ if ( (st0_tag == TW_Denormal) && (denormal_operand() < 0) )
+ return;
+
+ if ( signpositive(st1_ptr) )
+ FPU_copy_to_reg0(&CONST_INF, TAG_Special);
+ else
+ FPU_copy_to_reg0(&CONST_Z, TAG_Zero);
+ setsign(st0_ptr, sign);
+ return;
+
+ case TW_NaN:
+ real_2op_NaN(st1_ptr, st1_tag, 0, st0_ptr);
+ return;
+ }
+ }
+ else if ( st0_tag == TAG_Zero )
+ {
+ switch ( st1_tag )
+ {
+ case TAG_Valid:
+ case TAG_Zero:
+ return;
+
+ case TW_Denormal:
+ denormal_operand();
+ return;
+
+ case TW_Infinity:
+ if ( signpositive(st1_ptr) )
+ arith_invalid(0); /* Zero scaled by +Infinity */
+ return;
+
+ case TW_NaN:
+ real_2op_NaN(st1_ptr, st1_tag, 0, st0_ptr);
+ return;
+ }
+ }
+ else if ( st0_tag == TW_Infinity )
+ {
+ switch ( st1_tag )
+ {
+ case TAG_Valid:
+ case TAG_Zero:
+ return;
+
+ case TW_Denormal:
+ denormal_operand();
+ return;
+
+ case TW_Infinity:
+ if ( signnegative(st1_ptr) )
+ arith_invalid(0); /* Infinity scaled by -Infinity */
+ return;
+
+ case TW_NaN:
+ real_2op_NaN(st1_ptr, st1_tag, 0, st0_ptr);
+ return;
+ }
+ }
+ else if ( st0_tag == TW_NaN )
+ {
+ if ( st1_tag != TAG_Empty )
+ { real_2op_NaN(st1_ptr, st1_tag, 0, st0_ptr); return; }
+ }
+
+#ifdef PARANOID
+ if ( !((st0_tag == TAG_Empty) || (st1_tag == TAG_Empty)) )
+ {
+ EXCEPTION(EX_INTERNAL | 0x115);
+ return;
+ }
+#endif
+
+ /* At least one of st(0), st(1) must be empty */
+ FPU_stack_underflow();
+
+}
+
+
+/*---------------------------------------------------------------------------*/
+
+static FUNC_ST0 const trig_table_a[] = {
+ f2xm1, fyl2x, fptan, fpatan,
+ fxtract, fprem1, (FUNC_ST0)fdecstp, (FUNC_ST0)fincstp
+};
+
+void FPU_triga(void)
+{
+ (trig_table_a[FPU_rm])(&st(0), FPU_gettag0());
+}
+
+
+static FUNC_ST0 const trig_table_b[] =
+ {
+ fprem, fyl2xp1, fsqrt_, fsincos, frndint_, fscale, (FUNC_ST0)fsin, fcos
+ };
+
+void FPU_trigb(void)
+{
+ (trig_table_b[FPU_rm])(&st(0), FPU_gettag0());
+}