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-rw-r--r--arch/i386/math-emu/fpu_aux.c204
1 files changed, 204 insertions, 0 deletions
diff --git a/arch/i386/math-emu/fpu_aux.c b/arch/i386/math-emu/fpu_aux.c
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+/*---------------------------------------------------------------------------+
+ | 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 finit(void)
+{
+ control_word = 0x037f;
+ partial_status = 0;
+ top = 0; /* We don't keep top in the status word internally. */
+ fpu_tag_word = 0xffff;
+ /* The behaviour is different from that detailed in
+ Section 15.1.6 of the Intel manual */
+ operand_address.offset = 0;
+ operand_address.selector = 0;
+ instruction_address.offset = 0;
+ instruction_address.selector = 0;
+ instruction_address.opcode = 0;
+ no_ip_update = 1;
+}
+
+/*
+ * 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;
+}
+
+
+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();
+}
+