/*---------------------------------------------------------------------------+
|
/*---------------------------------------------------------------------------+
|
| reg_compare.c |
|
| reg_compare.c |
|
| |
|
| |
|
| Compare two floating point registers |
|
| Compare two floating point registers |
|
| |
|
| |
|
| Copyright (C) 1992,1993,1994 |
|
| Copyright (C) 1992,1993,1994 |
|
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
|
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, |
|
| Australia. E-mail billm@vaxc.cc.monash.edu.au |
|
| Australia. E-mail billm@vaxc.cc.monash.edu.au |
|
| |
|
| |
|
| |
|
| |
|
+---------------------------------------------------------------------------*/
|
+---------------------------------------------------------------------------*/
|
|
|
/*---------------------------------------------------------------------------+
|
/*---------------------------------------------------------------------------+
|
| compare() is the core FPU_REG comparison function |
|
| compare() is the core FPU_REG comparison function |
|
+---------------------------------------------------------------------------*/
|
+---------------------------------------------------------------------------*/
|
|
|
#include "fpu_system.h"
|
#include "fpu_system.h"
|
#include "exception.h"
|
#include "exception.h"
|
#include "fpu_emu.h"
|
#include "fpu_emu.h"
|
#include "control_w.h"
|
#include "control_w.h"
|
#include "status_w.h"
|
#include "status_w.h"
|
|
|
|
|
int compare(FPU_REG const *b)
|
int compare(FPU_REG const *b)
|
{
|
{
|
int diff;
|
int diff;
|
char st0_tag;
|
char st0_tag;
|
FPU_REG *st0_ptr;
|
FPU_REG *st0_ptr;
|
|
|
st0_ptr = &st(0);
|
st0_ptr = &st(0);
|
st0_tag = st0_ptr->tag;
|
st0_tag = st0_ptr->tag;
|
|
|
if ( st0_tag | b->tag )
|
if ( st0_tag | b->tag )
|
{
|
{
|
if ( st0_tag == TW_Zero )
|
if ( st0_tag == TW_Zero )
|
{
|
{
|
if ( b->tag == TW_Zero ) return COMP_A_eq_B;
|
if ( b->tag == TW_Zero ) return COMP_A_eq_B;
|
if ( b->tag == TW_Valid )
|
if ( b->tag == TW_Valid )
|
{
|
{
|
return ((b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
return ((b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
| ((b->exp <= EXP_UNDER) ?
|
| ((b->exp <= EXP_UNDER) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
}
|
}
|
else if ( b->tag == TW_Zero )
|
else if ( b->tag == TW_Zero )
|
{
|
{
|
if ( st0_tag == TW_Valid )
|
if ( st0_tag == TW_Valid )
|
{
|
{
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B
|
: COMP_A_lt_B)
|
: COMP_A_lt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
| ((st0_ptr->exp <= EXP_UNDER )
|
| ((st0_ptr->exp <= EXP_UNDER )
|
? COMP_Denormal : 0 )
|
? COMP_Denormal : 0 )
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
}
|
}
|
|
|
if ( st0_tag == TW_Infinity )
|
if ( st0_tag == TW_Infinity )
|
{
|
{
|
if ( (b->tag == TW_Valid) || (b->tag == TW_Zero) )
|
if ( (b->tag == TW_Valid) || (b->tag == TW_Zero) )
|
{
|
{
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B
|
: COMP_A_lt_B)
|
: COMP_A_lt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
| (((b->tag == TW_Valid) && (b->exp <= EXP_UNDER)) ?
|
| (((b->tag == TW_Valid) && (b->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0 )
|
COMP_Denormal : 0 )
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
else if ( b->tag == TW_Infinity )
|
else if ( b->tag == TW_Infinity )
|
{
|
{
|
/* The 80486 book says that infinities can be equal! */
|
/* The 80486 book says that infinities can be equal! */
|
return (st0_ptr->sign == b->sign) ? COMP_A_eq_B :
|
return (st0_ptr->sign == b->sign) ? COMP_A_eq_B :
|
((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
|
((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
|
}
|
}
|
/* Fall through to the NaN code */
|
/* Fall through to the NaN code */
|
}
|
}
|
else if ( b->tag == TW_Infinity )
|
else if ( b->tag == TW_Infinity )
|
{
|
{
|
if ( (st0_tag == TW_Valid) || (st0_tag == TW_Zero) )
|
if ( (st0_tag == TW_Valid) || (st0_tag == TW_Zero) )
|
{
|
{
|
return ((b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
return ((b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
| (((st0_tag == TW_Valid)
|
| (((st0_tag == TW_Valid)
|
&& (st0_ptr->exp <= EXP_UNDER)) ?
|
&& (st0_ptr->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
/* Fall through to the NaN code */
|
/* Fall through to the NaN code */
|
}
|
}
|
|
|
/* The only possibility now should be that one of the arguments
|
/* The only possibility now should be that one of the arguments
|
is a NaN */
|
is a NaN */
|
if ( (st0_tag == TW_NaN) || (b->tag == TW_NaN) )
|
if ( (st0_tag == TW_NaN) || (b->tag == TW_NaN) )
|
{
|
{
|
if ( ((st0_tag == TW_NaN) && !(st0_ptr->sigh & 0x40000000))
|
if ( ((st0_tag == TW_NaN) && !(st0_ptr->sigh & 0x40000000))
|
|| ((b->tag == TW_NaN) && !(b->sigh & 0x40000000)) )
|
|| ((b->tag == TW_NaN) && !(b->sigh & 0x40000000)) )
|
/* At least one arg is a signaling NaN */
|
/* At least one arg is a signaling NaN */
|
return COMP_No_Comp | COMP_SNaN | COMP_NaN;
|
return COMP_No_Comp | COMP_SNaN | COMP_NaN;
|
else
|
else
|
/* Neither is a signaling NaN */
|
/* Neither is a signaling NaN */
|
return COMP_No_Comp | COMP_NaN;
|
return COMP_No_Comp | COMP_NaN;
|
}
|
}
|
|
|
EXCEPTION(EX_Invalid);
|
EXCEPTION(EX_Invalid);
|
}
|
}
|
|
|
#ifdef PARANOID
|
#ifdef PARANOID
|
if (!(st0_ptr->sigh & 0x80000000)) EXCEPTION(EX_Invalid);
|
if (!(st0_ptr->sigh & 0x80000000)) EXCEPTION(EX_Invalid);
|
if (!(b->sigh & 0x80000000)) EXCEPTION(EX_Invalid);
|
if (!(b->sigh & 0x80000000)) EXCEPTION(EX_Invalid);
|
#endif PARANOID
|
#endif PARANOID
|
|
|
|
|
if (st0_ptr->sign != b->sign)
|
if (st0_ptr->sign != b->sign)
|
{
|
{
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
|
|
|
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
|
|
diff = st0_ptr->exp - b->exp;
|
diff = st0_ptr->exp - b->exp;
|
if ( diff == 0 )
|
if ( diff == 0 )
|
{
|
{
|
diff = st0_ptr->sigh - b->sigh; /* Works only if ms bits are
|
diff = st0_ptr->sigh - b->sigh; /* Works only if ms bits are
|
identical */
|
identical */
|
if ( diff == 0 )
|
if ( diff == 0 )
|
{
|
{
|
diff = st0_ptr->sigl > b->sigl;
|
diff = st0_ptr->sigl > b->sigl;
|
if ( diff == 0 )
|
if ( diff == 0 )
|
diff = -(st0_ptr->sigl < b->sigl);
|
diff = -(st0_ptr->sigl < b->sigl);
|
}
|
}
|
}
|
}
|
|
|
if ( diff > 0 )
|
if ( diff > 0 )
|
{
|
{
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
|
|
|
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
if ( diff < 0 )
|
if ( diff < 0 )
|
{
|
{
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
return ((st0_ptr->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
|
|
|
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
}
|
}
|
|
|
return COMP_A_eq_B
|
return COMP_A_eq_B
|
#ifdef DENORM_OPERAND
|
#ifdef DENORM_OPERAND
|
|
|
|
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
( ((st0_ptr->exp <= EXP_UNDER) || (b->exp <= EXP_UNDER)) ?
|
COMP_Denormal : 0)
|
COMP_Denormal : 0)
|
#endif DENORM_OPERAND
|
#endif DENORM_OPERAND
|
;
|
;
|
|
|
}
|
}
|
|
|
|
|
/* This function requires that st(0) is not empty */
|
/* This function requires that st(0) is not empty */
|
int compare_st_data(FPU_REG const *loaded_data)
|
int compare_st_data(FPU_REG const *loaded_data)
|
{
|
{
|
int f, c;
|
int f, c;
|
|
|
c = compare(loaded_data);
|
c = compare(loaded_data);
|
|
|
if (c & COMP_NaN)
|
if (c & COMP_NaN)
|
{
|
{
|
EXCEPTION(EX_Invalid);
|
EXCEPTION(EX_Invalid);
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
}
|
}
|
else
|
else
|
switch (c & 7)
|
switch (c & 7)
|
{
|
{
|
case COMP_A_lt_B:
|
case COMP_A_lt_B:
|
f = SW_C0;
|
f = SW_C0;
|
break;
|
break;
|
case COMP_A_eq_B:
|
case COMP_A_eq_B:
|
f = SW_C3;
|
f = SW_C3;
|
break;
|
break;
|
case COMP_A_gt_B:
|
case COMP_A_gt_B:
|
f = 0;
|
f = 0;
|
break;
|
break;
|
case COMP_No_Comp:
|
case COMP_No_Comp:
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#ifdef PARANOID
|
#ifdef PARANOID
|
default:
|
default:
|
EXCEPTION(EX_INTERNAL|0x121);
|
EXCEPTION(EX_INTERNAL|0x121);
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#endif PARANOID
|
#endif PARANOID
|
}
|
}
|
setcc(f);
|
setcc(f);
|
if (c & COMP_Denormal)
|
if (c & COMP_Denormal)
|
{
|
{
|
return denormal_operand();
|
return denormal_operand();
|
}
|
}
|
return 0;
|
return 0;
|
}
|
}
|
|
|
|
|
static int compare_st_st(int nr)
|
static int compare_st_st(int nr)
|
{
|
{
|
int f, c;
|
int f, c;
|
|
|
if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) )
|
if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) )
|
{
|
{
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
/* Stack fault */
|
/* Stack fault */
|
EXCEPTION(EX_StackUnder);
|
EXCEPTION(EX_StackUnder);
|
return !(control_word & CW_Invalid);
|
return !(control_word & CW_Invalid);
|
}
|
}
|
|
|
c = compare(&st(nr));
|
c = compare(&st(nr));
|
if (c & COMP_NaN)
|
if (c & COMP_NaN)
|
{
|
{
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
EXCEPTION(EX_Invalid);
|
EXCEPTION(EX_Invalid);
|
return !(control_word & CW_Invalid);
|
return !(control_word & CW_Invalid);
|
}
|
}
|
else
|
else
|
switch (c & 7)
|
switch (c & 7)
|
{
|
{
|
case COMP_A_lt_B:
|
case COMP_A_lt_B:
|
f = SW_C0;
|
f = SW_C0;
|
break;
|
break;
|
case COMP_A_eq_B:
|
case COMP_A_eq_B:
|
f = SW_C3;
|
f = SW_C3;
|
break;
|
break;
|
case COMP_A_gt_B:
|
case COMP_A_gt_B:
|
f = 0;
|
f = 0;
|
break;
|
break;
|
case COMP_No_Comp:
|
case COMP_No_Comp:
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#ifdef PARANOID
|
#ifdef PARANOID
|
default:
|
default:
|
EXCEPTION(EX_INTERNAL|0x122);
|
EXCEPTION(EX_INTERNAL|0x122);
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#endif PARANOID
|
#endif PARANOID
|
}
|
}
|
setcc(f);
|
setcc(f);
|
if (c & COMP_Denormal)
|
if (c & COMP_Denormal)
|
{
|
{
|
return denormal_operand();
|
return denormal_operand();
|
}
|
}
|
return 0;
|
return 0;
|
}
|
}
|
|
|
|
|
static int compare_u_st_st(int nr)
|
static int compare_u_st_st(int nr)
|
{
|
{
|
int f, c;
|
int f, c;
|
|
|
if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) )
|
if ( !NOT_EMPTY(0) || !NOT_EMPTY(nr) )
|
{
|
{
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
/* Stack fault */
|
/* Stack fault */
|
EXCEPTION(EX_StackUnder);
|
EXCEPTION(EX_StackUnder);
|
return !(control_word & CW_Invalid);
|
return !(control_word & CW_Invalid);
|
}
|
}
|
|
|
c = compare(&st(nr));
|
c = compare(&st(nr));
|
if (c & COMP_NaN)
|
if (c & COMP_NaN)
|
{
|
{
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
setcc(SW_C3 | SW_C2 | SW_C0);
|
if (c & COMP_SNaN) /* This is the only difference between
|
if (c & COMP_SNaN) /* This is the only difference between
|
un-ordered and ordinary comparisons */
|
un-ordered and ordinary comparisons */
|
{
|
{
|
EXCEPTION(EX_Invalid);
|
EXCEPTION(EX_Invalid);
|
return !(control_word & CW_Invalid);
|
return !(control_word & CW_Invalid);
|
}
|
}
|
return 0;
|
return 0;
|
}
|
}
|
else
|
else
|
switch (c & 7)
|
switch (c & 7)
|
{
|
{
|
case COMP_A_lt_B:
|
case COMP_A_lt_B:
|
f = SW_C0;
|
f = SW_C0;
|
break;
|
break;
|
case COMP_A_eq_B:
|
case COMP_A_eq_B:
|
f = SW_C3;
|
f = SW_C3;
|
break;
|
break;
|
case COMP_A_gt_B:
|
case COMP_A_gt_B:
|
f = 0;
|
f = 0;
|
break;
|
break;
|
case COMP_No_Comp:
|
case COMP_No_Comp:
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#ifdef PARANOID
|
#ifdef PARANOID
|
default:
|
default:
|
EXCEPTION(EX_INTERNAL|0x123);
|
EXCEPTION(EX_INTERNAL|0x123);
|
f = SW_C3 | SW_C2 | SW_C0;
|
f = SW_C3 | SW_C2 | SW_C0;
|
break;
|
break;
|
#endif PARANOID
|
#endif PARANOID
|
}
|
}
|
setcc(f);
|
setcc(f);
|
if (c & COMP_Denormal)
|
if (c & COMP_Denormal)
|
{
|
{
|
return denormal_operand();
|
return denormal_operand();
|
}
|
}
|
return 0;
|
return 0;
|
}
|
}
|
|
|
/*---------------------------------------------------------------------------*/
|
/*---------------------------------------------------------------------------*/
|
|
|
void fcom_st()
|
void fcom_st()
|
{
|
{
|
/* fcom st(i) */
|
/* fcom st(i) */
|
compare_st_st(FPU_rm);
|
compare_st_st(FPU_rm);
|
}
|
}
|
|
|
|
|
void fcompst()
|
void fcompst()
|
{
|
{
|
/* fcomp st(i) */
|
/* fcomp st(i) */
|
if ( !compare_st_st(FPU_rm) )
|
if ( !compare_st_st(FPU_rm) )
|
pop();
|
pop();
|
}
|
}
|
|
|
|
|
void fcompp()
|
void fcompp()
|
{
|
{
|
/* fcompp */
|
/* fcompp */
|
if (FPU_rm != 1)
|
if (FPU_rm != 1)
|
{
|
{
|
FPU_illegal();
|
FPU_illegal();
|
return;
|
return;
|
}
|
}
|
if ( !compare_st_st(1) )
|
if ( !compare_st_st(1) )
|
poppop();
|
poppop();
|
}
|
}
|
|
|
|
|
void fucom_()
|
void fucom_()
|
{
|
{
|
/* fucom st(i) */
|
/* fucom st(i) */
|
compare_u_st_st(FPU_rm);
|
compare_u_st_st(FPU_rm);
|
|
|
}
|
}
|
|
|
|
|
void fucomp()
|
void fucomp()
|
{
|
{
|
/* fucomp st(i) */
|
/* fucomp st(i) */
|
if ( !compare_u_st_st(FPU_rm) )
|
if ( !compare_u_st_st(FPU_rm) )
|
pop();
|
pop();
|
}
|
}
|
|
|
|
|
void fucompp()
|
void fucompp()
|
{
|
{
|
/* fucompp */
|
/* fucompp */
|
if (FPU_rm == 1)
|
if (FPU_rm == 1)
|
{
|
{
|
if ( !compare_u_st_st(1) )
|
if ( !compare_u_st_st(1) )
|
poppop();
|
poppop();
|
}
|
}
|
else
|
else
|
FPU_illegal();
|
FPU_illegal();
|
}
|
}
|
|
|
