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|
/*---------------------------------------------------------------------------+
| fpu_tags.c |
| |
| Set FPU register tags. |
| |
| Copyright (C) 1997 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
| E-mail billm@jacobi.maths.monash.edu.au |
| |
| |
+---------------------------------------------------------------------------*/
#include "fpu_emu.h"
#include "fpu_system.h"
#include "exception.h"
void FPU_pop(void)
{
fpu_tag_word |= 3 << ((top & 7)*2);
top++;
}
int FPU_gettag0(void)
{
return (fpu_tag_word >> ((top & 7)*2)) & 3;
}
int FPU_gettagi(int stnr)
{
return (fpu_tag_word >> (((top+stnr) & 7)*2)) & 3;
}
int FPU_gettag(int regnr)
{
return (fpu_tag_word >> ((regnr & 7)*2)) & 3;
}
void FPU_settag0(int tag)
{
int regnr = top;
regnr &= 7;
fpu_tag_word &= ~(3 << (regnr*2));
fpu_tag_word |= (tag & 3) << (regnr*2);
}
void FPU_settagi(int stnr, int tag)
{
int regnr = stnr+top;
regnr &= 7;
fpu_tag_word &= ~(3 << (regnr*2));
fpu_tag_word |= (tag & 3) << (regnr*2);
}
void FPU_settag(int regnr, int tag)
{
regnr &= 7;
fpu_tag_word &= ~(3 << (regnr*2));
fpu_tag_word |= (tag & 3) << (regnr*2);
}
int FPU_Special(FPU_REG const *ptr)
{
int exp = exponent(ptr);
if ( exp == EXP_BIAS+EXP_UNDER )
return TW_Denormal;
else if ( exp != EXP_BIAS+EXP_OVER )
return TW_NaN;
else if ( (ptr->sigh == 0x80000000) && (ptr->sigl == 0) )
return TW_Infinity;
return TW_NaN;
}
int isNaN(FPU_REG const *ptr)
{
return ( (exponent(ptr) == EXP_BIAS+EXP_OVER)
&& !((ptr->sigh == 0x80000000) && (ptr->sigl == 0)) );
}
int FPU_empty_i(int stnr)
{
int regnr = (top+stnr) & 7;
return ((fpu_tag_word >> (regnr*2)) & 3) == TAG_Empty;
}
int FPU_stackoverflow(FPU_REG **st_new_ptr)
{
*st_new_ptr = &st(-1);
return ((fpu_tag_word >> (((top - 1) & 7)*2)) & 3) != TAG_Empty;
}
void FPU_copy_to_regi(FPU_REG const *r, u_char tag, int stnr)
{
reg_copy(r, &st(stnr));
FPU_settagi(stnr, tag);
}
void FPU_copy_to_reg1(FPU_REG const *r, u_char tag)
{
reg_copy(r, &st(1));
FPU_settagi(1, tag);
}
void FPU_copy_to_reg0(FPU_REG const *r, u_char tag)
{
int regnr = top;
regnr &= 7;
reg_copy(r, &st(0));
fpu_tag_word &= ~(3 << (regnr*2));
fpu_tag_word |= (tag & 3) << (regnr*2);
}
|
