freebsd-dev/sys/gnu/i386/fpemul/reg_compare.c
1994-08-31 04:45:24 +00:00

385 lines
9.4 KiB
C

/*
* reg_compare.c
*
* Compare two floating point registers
*
*
* Copyright (C) 1992,1993,1994
* W. Metzenthen, 22 Parker St, Ormond, Vic 3163,
* Australia. E-mail billm@vaxc.cc.monash.edu.au
* All rights reserved.
*
* This copyright notice covers the redistribution and use of the
* FPU emulator developed by W. Metzenthen. It covers only its use
* in the 386BSD, FreeBSD and NetBSD operating systems. Any other
* use is not permitted under this copyright.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must include information specifying
* that source code for the emulator is freely available and include
* either:
* a) an offer to provide the source code for a nominal distribution
* fee, or
* b) list at least two alternative methods whereby the source
* can be obtained, e.g. a publically accessible bulletin board
* and an anonymous ftp site from which the software can be
* downloaded.
* 3. All advertising materials specifically mentioning features or use of
* this emulator must acknowledge that it was developed by W. Metzenthen.
* 4. The name of W. Metzenthen may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* W. METZENTHEN BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*
* The purpose of this copyright, based upon the Berkeley copyright, is to
* ensure that the covered software remains freely available to everyone.
*
* The software (with necessary differences) is also available, but under
* the terms of the GNU copyleft, for the Linux operating system and for
* the djgpp ms-dos extender.
*
* W. Metzenthen June 1994.
*
*
* $Id: reg_compare.c,v 1.3 1994/06/10 07:44:47 rich Exp $
*
*/
/*---------------------------------------------------------------------------+
| compare() is the core FPU_REG comparison function |
+---------------------------------------------------------------------------*/
#include "param.h"
#include "proc.h"
#include "systm.h"
#include "machine/cpu.h"
#include "machine/pcb.h"
#include "fpu_emu.h"
#include "fpu_system.h"
#include "exception.h"
#include "control_w.h"
#include "status_w.h"
int
compare(FPU_REG * b)
{
int diff;
if (FPU_st0_ptr->tag | b->tag) {
if (FPU_st0_ptr->tag == TW_Zero) {
if (b->tag == TW_Zero)
return COMP_A_eq_B;
if (b->tag == TW_Valid) {
#ifdef DENORM_OPERAND
if ((b->exp <= EXP_UNDER) && (denormal_operand()))
return COMP_Denormal;
#endif /* DENORM_OPERAND */
return (b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B;
}
} else
if (b->tag == TW_Zero) {
if (FPU_st0_ptr->tag == TW_Valid) {
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->exp <= EXP_UNDER) && (denormal_operand()))
return COMP_Denormal;
#endif /* DENORM_OPERAND */
return (FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B;
}
}
if (FPU_st0_ptr->tag == TW_Infinity) {
if ((b->tag == TW_Valid) || (b->tag == TW_Zero)) {
#ifdef DENORM_OPERAND
if ((b->tag == TW_Valid) && (b->exp <= EXP_UNDER)
&& (denormal_operand()))
return COMP_Denormal;
#endif /* DENORM_OPERAND */
return (FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B;
} else
if (b->tag == TW_Infinity) {
/* The 80486 book says that infinities
* can be equal! */
return (FPU_st0_ptr->sign == b->sign) ? COMP_A_eq_B :
((FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
}
/* Fall through to the NaN code */
} else
if (b->tag == TW_Infinity) {
if ((FPU_st0_ptr->tag == TW_Valid) || (FPU_st0_ptr->tag == TW_Zero)) {
#ifdef DENORM_OPERAND
if ((FPU_st0_ptr->tag == TW_Valid)
&& (FPU_st0_ptr->exp <= EXP_UNDER)
&& (denormal_operand()))
return COMP_Denormal;
#endif /* DENORM_OPERAND */
return (b->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B;
}
/* Fall through to the NaN code */
}
/* The only possibility now should be that one of the
* arguments is a NaN */
if ((FPU_st0_ptr->tag == TW_NaN) || (b->tag == TW_NaN)) {
if (((FPU_st0_ptr->tag == TW_NaN) && !(FPU_st0_ptr->sigh & 0x40000000))
|| ((b->tag == TW_NaN) && !(b->sigh & 0x40000000)))
/* At least one arg is a signaling NaN */
return COMP_No_Comp | COMP_SNaN | COMP_NaN;
else
/* Neither is a signaling NaN */
return COMP_No_Comp | COMP_NaN;
}
EXCEPTION(EX_Invalid);
}
#ifdef PARANOID
if (!(FPU_st0_ptr->sigh & 0x80000000))
EXCEPTION(EX_Invalid);
if (!(b->sigh & 0x80000000))
EXCEPTION(EX_Invalid);
#endif /* PARANOID */
#ifdef DENORM_OPERAND
if (((FPU_st0_ptr->exp <= EXP_UNDER) ||
(b->exp <= EXP_UNDER)) && (denormal_operand()))
return COMP_Denormal;
#endif /* DENORM_OPERAND */
if (FPU_st0_ptr->sign != b->sign)
return (FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B;
diff = FPU_st0_ptr->exp - b->exp;
if (diff == 0) {
diff = FPU_st0_ptr->sigh - b->sigh; /* Works only if ms bits
* are identical */
if (diff == 0) {
diff = FPU_st0_ptr->sigl > b->sigl;
if (diff == 0)
diff = -(FPU_st0_ptr->sigl < b->sigl);
}
}
if (diff > 0)
return (FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B;
if (diff < 0)
return (FPU_st0_ptr->sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B;
return COMP_A_eq_B;
}
/* This function requires that st(0) is not empty */
int
compare_st_data(void)
{
int f = 0, c;
c = compare(&FPU_loaded_data);
if (c & (COMP_NaN | COMP_Denormal)) {
if (c & COMP_NaN) {
EXCEPTION(EX_Invalid);
f = SW_C3 | SW_C2 | SW_C0;
} else {
/* One of the operands is a de-normal */
return 0;
}
} else
switch (c) {
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 /* PARANOID */
}
setcc(f);
return 1;
}
static int
compare_st_st(int nr)
{
int f = 0, c;
if (!NOT_EMPTY_0 || !NOT_EMPTY(nr)) {
setcc(SW_C3 | SW_C2 | SW_C0);
/* Stack fault */
EXCEPTION(EX_StackUnder);
return control_word & CW_Invalid;
}
c = compare(&st(nr));
if (c & (COMP_NaN | COMP_Denormal)) {
if (c & COMP_NaN) {
setcc(SW_C3 | SW_C2 | SW_C0);
EXCEPTION(EX_Invalid);
return control_word & CW_Invalid;
} else {
/* One of the operands is a de-normal */
return control_word & CW_Denormal;
}
} else
switch (c) {
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 | 0x122);
f = SW_C3 | SW_C2 | SW_C0;
break;
#endif /* PARANOID */
}
setcc(f);
return 1;
}
static int
compare_u_st_st(int nr)
{
int f = 0, c;
if (!NOT_EMPTY_0 || !NOT_EMPTY(nr)) {
setcc(SW_C3 | SW_C2 | SW_C0);
/* Stack fault */
EXCEPTION(EX_StackUnder);
return control_word & CW_Invalid;
}
c = compare(&st(nr));
if (c & (COMP_NaN | COMP_Denormal)) {
if (c & COMP_NaN) {
setcc(SW_C3 | SW_C2 | SW_C0);
if (c & COMP_SNaN) { /* This is the only difference
* between un-ordered and
* ordinary comparisons */
EXCEPTION(EX_Invalid);
return control_word & CW_Invalid;
}
return 1;
} else {
/* One of the operands is a de-normal */
return control_word & CW_Denormal;
}
} else
switch (c) {
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 /* PARANOID */
}
setcc(f);
return 1;
}
/*---------------------------------------------------------------------------*/
void
fcom_st()
{
/* fcom st(i) */
compare_st_st(FPU_rm);
}
void
fcompst()
{
/* fcomp st(i) */
if (compare_st_st(FPU_rm))
pop();
}
void
fcompp()
{
/* fcompp */
if (FPU_rm != 1)
return Un_impl();
if (compare_st_st(1)) {
pop();
FPU_st0_ptr = &st(0);
pop();
}
}
void
fucom_()
{
/* fucom st(i) */
compare_u_st_st(FPU_rm);
}
void
fucomp()
{
/* fucomp st(i) */
if (compare_u_st_st(FPU_rm))
pop();
}
void
fucompp()
{
/* fucompp */
if (FPU_rm == 1) {
if (compare_u_st_st(1)) {
pop();
FPU_st0_ptr = &st(0);
pop();
}
} else
Un_impl();
}