fpu_tags.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*---------------------------------------------------------------------------+
  3 |  fpu_tags.c                                                               |
  4 |                                                                           |
  5 |  Set FPU register tags.                                                   |
  6 |                                                                           |
  7 | Copyright (C) 1997                                                        |
  8 |                  W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
  9 |                  E-mail   billm@jacobi.maths.monash.edu.au                |
 10 |                                                                           |
 11 |                                                                           |
 12 +---------------------------------------------------------------------------*/
 13
 14#include "fpu_emu.h"
 15#include "fpu_system.h"
 16#include "exception.h"
 17
 18void FPU_pop(void)
 19{
 20	fpu_tag_word |= 3 << ((top & 7) * 2);
 21	top++;
 22}
 23
 24int FPU_gettag0(void)
 25{
 26	return (fpu_tag_word >> ((top & 7) * 2)) & 3;
 27}
 28
 29int FPU_gettagi(int stnr)
 30{
 31	return (fpu_tag_word >> (((top + stnr) & 7) * 2)) & 3;
 32}
 33
 34int FPU_gettag(int regnr)
 35{
 36	return (fpu_tag_word >> ((regnr & 7) * 2)) & 3;
 37}
 38
 39void FPU_settag0(int tag)
 40{
 41	int regnr = top;
 42	regnr &= 7;
 43	fpu_tag_word &= ~(3 << (regnr * 2));
 44	fpu_tag_word |= (tag & 3) << (regnr * 2);
 45}
 46
 47void FPU_settagi(int stnr, int tag)
 48{
 49	int regnr = stnr + top;
 50	regnr &= 7;
 51	fpu_tag_word &= ~(3 << (regnr * 2));
 52	fpu_tag_word |= (tag & 3) << (regnr * 2);
 53}
 54
 55void FPU_settag(int regnr, int tag)
 56{
 57	regnr &= 7;
 58	fpu_tag_word &= ~(3 << (regnr * 2));
 59	fpu_tag_word |= (tag & 3) << (regnr * 2);
 60}
 61
 62int FPU_Special(FPU_REG const *ptr)
 63{
 64	int exp = exponent(ptr);
 65
 66	if (exp == EXP_BIAS + EXP_UNDER)
 67		return TW_Denormal;
 68	else if (exp != EXP_BIAS + EXP_OVER)
 69		return TW_NaN;
 70	else if ((ptr->sigh == 0x80000000) && (ptr->sigl == 0))
 71		return TW_Infinity;
 72	return TW_NaN;
 73}
 74
 75int isNaN(FPU_REG const *ptr)
 76{
 77	return ((exponent(ptr) == EXP_BIAS + EXP_OVER)
 78		&& !((ptr->sigh == 0x80000000) && (ptr->sigl == 0)));
 79}
 80
 81int FPU_empty_i(int stnr)
 82{
 83	int regnr = (top + stnr) & 7;
 84
 85	return ((fpu_tag_word >> (regnr * 2)) & 3) == TAG_Empty;
 86}
 87
 88int FPU_stackoverflow(FPU_REG ** st_new_ptr)
 89{
 90	*st_new_ptr = &st(-1);
 91
 92	return ((fpu_tag_word >> (((top - 1) & 7) * 2)) & 3) != TAG_Empty;
 93}
 94
 95void FPU_copy_to_regi(FPU_REG const *r, u_char tag, int stnr)
 96{
 97	reg_copy(r, &st(stnr));
 98	FPU_settagi(stnr, tag);
 99}
100
101void FPU_copy_to_reg1(FPU_REG const *r, u_char tag)
102{
103	reg_copy(r, &st(1));
104	FPU_settagi(1, tag);
105}
106
107void FPU_copy_to_reg0(FPU_REG const *r, u_char tag)
108{
109	int regnr = top;
110	regnr &= 7;
111
112	reg_copy(r, &st(0));
113
114	fpu_tag_word &= ~(3 << (regnr * 2));
115	fpu_tag_word |= (tag & 3) << (regnr * 2);
116}