// SPDX-License-Identifier: GPL-2.0
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/*---------------------------------------------------------------------------+
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| fpu_aux.c |
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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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{
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}
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static void fclex(void)
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{
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partial_status &=
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~(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 fpstate_init_soft(struct swregs_state *soft)
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{
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struct address *oaddr, *iaddr;
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memset(soft, 0, sizeof(*soft));
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soft->cwd = 0x037f;
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soft->swd = 0;
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soft->ftop = 0; /* We don't keep top in the status word internally. */
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soft->twd = 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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oaddr = (struct address *)&soft->foo;
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oaddr->offset = 0;
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oaddr->selector = 0;
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iaddr = (struct address *)&soft->fip;
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iaddr->offset = 0;
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iaddr->selector = 0;
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iaddr->opcode = 0;
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soft->no_update = 1;
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}
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void finit(void)
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{
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fpstate_init_soft(¤t->thread.fpu.state.soft);
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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_(void)
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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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*(short *)&FPU_EAX = 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_(void)
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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(void)
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{
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(fp_nop_table[FPU_rm]) ();
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}
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void fld_i_(void)
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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 (STACK_OVERFLOW) {
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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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reg_copy(&st(i), st_new_ptr);
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tag = FPU_gettagi(i);
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push();
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FPU_settag0(tag);
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} else {
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if (control_word & CW_Invalid) {
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/* The masked response */
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FPU_stack_underflow();
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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(void)
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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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long tag_word = fpu_tag_word;
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int regnr = top & 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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if (st0_tag == TAG_Empty) {
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if (sti_tag == TAG_Empty) {
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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 (control_word & CW_Invalid) {
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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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if (control_word & CW_Invalid) {
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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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clear_C1();
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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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static void fcmovCC(void)
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{
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/* fcmovCC st(i) */
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int i = FPU_rm;
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FPU_REG *st0_ptr = &st(0);
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FPU_REG *sti_ptr = &st(i);
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long tag_word = fpu_tag_word;
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int regnr = top & 7;
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int regnri = (top + i) & 7;
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u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
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if (sti_tag == TAG_Empty) {
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FPU_stack_underflow();
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clear_C1();
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return;
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}
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reg_copy(sti_ptr, st0_ptr);
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tag_word &= ~(3 << (regnr * 2));
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tag_word |= (sti_tag << (regnr * 2));
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fpu_tag_word = tag_word;
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}
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void fcmovb(void)
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{
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if (FPU_EFLAGS & X86_EFLAGS_CF)
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fcmovCC();
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}
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void fcmove(void)
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{
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if (FPU_EFLAGS & X86_EFLAGS_ZF)
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fcmovCC();
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}
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void fcmovbe(void)
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{
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if (FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF))
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fcmovCC();
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}
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void fcmovu(void)
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{
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if (FPU_EFLAGS & X86_EFLAGS_PF)
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fcmovCC();
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}
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void fcmovnb(void)
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{
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if (!(FPU_EFLAGS & X86_EFLAGS_CF))
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fcmovCC();
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}
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void fcmovne(void)
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{
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if (!(FPU_EFLAGS & X86_EFLAGS_ZF))
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fcmovCC();
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}
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void fcmovnbe(void)
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{
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if (!(FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF)))
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fcmovCC();
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}
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void fcmovnu(void)
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{
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if (!(FPU_EFLAGS & X86_EFLAGS_PF))
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fcmovCC();
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}
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void ffree_(void)
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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 ffreep(void)
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{
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/* ffree st(i) + pop - unofficial code */
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FPU_settagi(FPU_rm, TAG_Empty);
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FPU_pop();
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}
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void fst_i_(void)
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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(void)
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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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