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-rw-r--r--arch/x86/math-emu/fpu_aux.c267
1 files changed, 267 insertions, 0 deletions
diff --git a/arch/x86/math-emu/fpu_aux.c b/arch/x86/math-emu/fpu_aux.c
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+++ b/arch/x86/math-emu/fpu_aux.c
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+// SPDX-License-Identifier: GPL-2.0
+/*---------------------------------------------------------------------------+
+ | fpu_aux.c |
+ | |
+ | Code to implement some of the FPU auxiliary instructions. |
+ | |
+ | Copyright (C) 1992,1993,1994,1997 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
+ | E-mail billm@suburbia.net |
+ | |
+ | |
+ +---------------------------------------------------------------------------*/
+
+#include "fpu_system.h"
+#include "exception.h"
+#include "fpu_emu.h"
+#include "status_w.h"
+#include "control_w.h"
+
+static void fnop(void)
+{
+}
+
+static void fclex(void)
+{
+ partial_status &=
+ ~(SW_Backward | SW_Summary | SW_Stack_Fault | SW_Precision |
+ SW_Underflow | SW_Overflow | SW_Zero_Div | SW_Denorm_Op |
+ SW_Invalid);
+ no_ip_update = 1;
+}
+
+/* Needs to be externally visible */
+void fpstate_init_soft(struct swregs_state *soft)
+{
+ struct address *oaddr, *iaddr;
+ memset(soft, 0, sizeof(*soft));
+ soft->cwd = 0x037f;
+ soft->swd = 0;
+ soft->ftop = 0; /* We don't keep top in the status word internally. */
+ soft->twd = 0xffff;
+ /* The behaviour is different from that detailed in
+ Section 15.1.6 of the Intel manual */
+ oaddr = (struct address *)&soft->foo;
+ oaddr->offset = 0;
+ oaddr->selector = 0;
+ iaddr = (struct address *)&soft->fip;
+ iaddr->offset = 0;
+ iaddr->selector = 0;
+ iaddr->opcode = 0;
+ soft->no_update = 1;
+}
+
+void finit(void)
+{
+ fpstate_init_soft(&current->thread.fpu.fpstate->regs.soft);
+}
+
+/*
+ * These are nops on the i387..
+ */
+#define feni fnop
+#define fdisi fnop
+#define fsetpm fnop
+
+static FUNC const finit_table[] = {
+ feni, fdisi, fclex, finit,
+ fsetpm, FPU_illegal, FPU_illegal, FPU_illegal
+};
+
+void finit_(void)
+{
+ (finit_table[FPU_rm]) ();
+}
+
+static void fstsw_ax(void)
+{
+ *(short *)&FPU_EAX = status_word();
+ no_ip_update = 1;
+}
+
+static FUNC const fstsw_table[] = {
+ fstsw_ax, FPU_illegal, FPU_illegal, FPU_illegal,
+ FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
+};
+
+void fstsw_(void)
+{
+ (fstsw_table[FPU_rm]) ();
+}
+
+static FUNC const fp_nop_table[] = {
+ fnop, FPU_illegal, FPU_illegal, FPU_illegal,
+ FPU_illegal, FPU_illegal, FPU_illegal, FPU_illegal
+};
+
+void fp_nop(void)
+{
+ (fp_nop_table[FPU_rm]) ();
+}
+
+void fld_i_(void)
+{
+ FPU_REG *st_new_ptr;
+ int i;
+ u_char tag;
+
+ if (STACK_OVERFLOW) {
+ FPU_stack_overflow();
+ return;
+ }
+
+ /* fld st(i) */
+ i = FPU_rm;
+ if (NOT_EMPTY(i)) {
+ reg_copy(&st(i), st_new_ptr);
+ tag = FPU_gettagi(i);
+ push();
+ FPU_settag0(tag);
+ } else {
+ if (control_word & CW_Invalid) {
+ /* The masked response */
+ FPU_stack_underflow();
+ } else
+ EXCEPTION(EX_StackUnder);
+ }
+
+}
+
+void fxch_i(void)
+{
+ /* fxch st(i) */
+ FPU_REG t;
+ int i = FPU_rm;
+ FPU_REG *st0_ptr = &st(0), *sti_ptr = &st(i);
+ long tag_word = fpu_tag_word;
+ int regnr = top & 7, regnri = ((regnr + i) & 7);
+ u_char st0_tag = (tag_word >> (regnr * 2)) & 3;
+ u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
+
+ if (st0_tag == TAG_Empty) {
+ if (sti_tag == TAG_Empty) {
+ FPU_stack_underflow();
+ FPU_stack_underflow_i(i);
+ return;
+ }
+ if (control_word & CW_Invalid) {
+ /* Masked response */
+ FPU_copy_to_reg0(sti_ptr, sti_tag);
+ }
+ FPU_stack_underflow_i(i);
+ return;
+ }
+ if (sti_tag == TAG_Empty) {
+ if (control_word & CW_Invalid) {
+ /* Masked response */
+ FPU_copy_to_regi(st0_ptr, st0_tag, i);
+ }
+ FPU_stack_underflow();
+ return;
+ }
+ clear_C1();
+
+ reg_copy(st0_ptr, &t);
+ reg_copy(sti_ptr, st0_ptr);
+ reg_copy(&t, sti_ptr);
+
+ tag_word &= ~(3 << (regnr * 2)) & ~(3 << (regnri * 2));
+ tag_word |= (sti_tag << (regnr * 2)) | (st0_tag << (regnri * 2));
+ fpu_tag_word = tag_word;
+}
+
+static void fcmovCC(void)
+{
+ /* fcmovCC st(i) */
+ int i = FPU_rm;
+ FPU_REG *st0_ptr = &st(0);
+ FPU_REG *sti_ptr = &st(i);
+ long tag_word = fpu_tag_word;
+ int regnr = top & 7;
+ int regnri = (top + i) & 7;
+ u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
+
+ if (sti_tag == TAG_Empty) {
+ FPU_stack_underflow();
+ clear_C1();
+ return;
+ }
+ reg_copy(sti_ptr, st0_ptr);
+ tag_word &= ~(3 << (regnr * 2));
+ tag_word |= (sti_tag << (regnr * 2));
+ fpu_tag_word = tag_word;
+}
+
+void fcmovb(void)
+{
+ if (FPU_EFLAGS & X86_EFLAGS_CF)
+ fcmovCC();
+}
+
+void fcmove(void)
+{
+ if (FPU_EFLAGS & X86_EFLAGS_ZF)
+ fcmovCC();
+}
+
+void fcmovbe(void)
+{
+ if (FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF))
+ fcmovCC();
+}
+
+void fcmovu(void)
+{
+ if (FPU_EFLAGS & X86_EFLAGS_PF)
+ fcmovCC();
+}
+
+void fcmovnb(void)
+{
+ if (!(FPU_EFLAGS & X86_EFLAGS_CF))
+ fcmovCC();
+}
+
+void fcmovne(void)
+{
+ if (!(FPU_EFLAGS & X86_EFLAGS_ZF))
+ fcmovCC();
+}
+
+void fcmovnbe(void)
+{
+ if (!(FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF)))
+ fcmovCC();
+}
+
+void fcmovnu(void)
+{
+ if (!(FPU_EFLAGS & X86_EFLAGS_PF))
+ fcmovCC();
+}
+
+void ffree_(void)
+{
+ /* ffree st(i) */
+ FPU_settagi(FPU_rm, TAG_Empty);
+}
+
+void ffreep(void)
+{
+ /* ffree st(i) + pop - unofficial code */
+ FPU_settagi(FPU_rm, TAG_Empty);
+ FPU_pop();
+}
+
+void fst_i_(void)
+{
+ /* fst st(i) */
+ FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
+}
+
+void fstp_i(void)
+{
+ /* fstp st(i) */
+ FPU_copy_to_regi(&st(0), FPU_gettag0(), FPU_rm);
+ FPU_pop();
+}