191 lines
4.2 KiB
C
191 lines
4.2 KiB
C
/*---------------------------------------------------------------------------+
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| fpu_aux.c |
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| $Id: fpu_aux.c,v 1.7 2003-11-01 18:36:19 sshwarts Exp $
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| Code to implement some of the FPU auxiliary instructions. |
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| Copyright (C) 1992,1993,1994,1997 |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
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| E-mail billm@suburbia.net |
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+---------------------------------------------------------------------------*/
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#include "fpu_system.h"
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#include "exception.h"
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#include "fpu_emu.h"
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#include "status_w.h"
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#include "control_w.h"
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static void fnop(void) { }
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void fclex(void)
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{
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FPU_partial_status &= ~(SW_Backward|SW_Summary|SW_Stack_Fault|SW_Precision|
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SW_Underflow|SW_Overflow|SW_Zero_Div|SW_Denorm_Op|
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SW_Invalid);
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no_ip_update = 1;
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}
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/* Needs to be externally visible */
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void finit()
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{
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FPU_control_word = 0x037f;
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FPU_partial_status = 0;
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FPU_tos = 0; /* We don't keep top in the status word internally. */
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FPU_tag_word = 0xffff;
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/* The behaviour is different from that detailed in
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Section 15.1.6 of the Intel manual */
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FPU_operand_address.offset = 0;
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FPU_operand_address.selector = 0;
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FPU_instruction_address.offset = 0;
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FPU_instruction_address.selector = 0;
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FPU_instruction_address.opcode = 0;
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no_ip_update = 1;
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}
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/*
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* These are nops on the i387..
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*/
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#define feni fnop
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#define fdisi fnop
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#define fsetpm fnop
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static FUNC const finit_table[] = {
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feni, fdisi, fclex, finit,
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fsetpm, FPU_illegal, FPU_illegal, FPU_illegal
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};
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void finit_()
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{
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(finit_table[FPU_rm])();
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}
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static void fstsw_ax(void)
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{
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fpu_set_ax(status_word());
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no_ip_update = 1;
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}
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static FUNC const fstsw_table[] = {
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fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,
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FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
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};
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void fstsw_()
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{
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(fstsw_table[FPU_rm])();
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}
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static FUNC const fp_nop_table[] = {
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fnop, FPU_illegal, FPU_illegal, FPU_illegal,
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FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
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};
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void fp_nop()
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{
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(fp_nop_table[FPU_rm])();
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}
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void fld_i_()
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{
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FPU_REG *st_new_ptr;
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int i;
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u_char tag;
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if (FPU_stackoverflow(&st_new_ptr))
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{ FPU_stack_overflow();
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return;
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}
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/* fld st(i) */
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i = FPU_rm;
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if ( NOT_EMPTY(i) )
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{
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reg_copy(&st(i), st_new_ptr);
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tag = FPU_gettagi(i);
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FPU_push();
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FPU_settag0(tag);
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}
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else
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{
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if ( FPU_control_word & CW_Invalid )
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{
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/* The masked response */
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FPU_stack_underflow();
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}
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else
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EXCEPTION(EX_StackUnder);
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}
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}
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void fxch_i()
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{
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/* fxch st(i) */
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FPU_REG t;
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int i = FPU_rm;
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FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i);
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s32 tag_word = FPU_tag_word;
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int regnr = FPU_tos & 7, regnri = ((regnr + i) & 7);
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u_char st0_tag = (tag_word >> (regnr*2)) & 3;
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u_char sti_tag = (tag_word >> (regnri*2)) & 3;
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clear_C1();
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if ( st0_tag == TAG_Empty )
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{
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if ( sti_tag == TAG_Empty )
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{
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FPU_stack_underflow();
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FPU_stack_underflow_i(i);
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return;
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}
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if ( FPU_control_word & CW_Invalid )
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{
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/* Masked response */
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FPU_copy_to_reg0(sti_ptr, sti_tag);
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}
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FPU_stack_underflow_i(i);
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return;
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}
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if ( sti_tag == TAG_Empty )
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{
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if ( FPU_control_word & CW_Invalid )
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{
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/* Masked response */
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FPU_copy_to_regi(st0_ptr, st0_tag, i);
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}
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FPU_stack_underflow();
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return;
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}
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reg_copy(st0_ptr, &t);
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reg_copy(sti_ptr, st0_ptr);
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reg_copy(&t, sti_ptr);
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tag_word &= ~(3 << (regnr*2)) & ~(3 << (regnri*2));
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tag_word |= (sti_tag << (regnr*2)) | (st0_tag << (regnri*2));
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FPU_tag_word = tag_word;
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}
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void ffree_()
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{
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/* ffree st(i) */
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FPU_settagi(FPU_rm, TAG_Empty);
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}
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void fst_i_()
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{
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/* fst st(i) */
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FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
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}
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void fstp_i()
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{
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/* fstp st(i) */
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FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
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FPU_pop();
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}
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