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-rw-r--r--arch/x86/math-emu/reg_compare.c479
1 files changed, 479 insertions, 0 deletions
diff --git a/arch/x86/math-emu/reg_compare.c b/arch/x86/math-emu/reg_compare.c
new file mode 100644
index 000000000..eacb5128f
--- /dev/null
+++ b/arch/x86/math-emu/reg_compare.c
@@ -0,0 +1,479 @@
+// SPDX-License-Identifier: GPL-2.0
+/*---------------------------------------------------------------------------+
+ | reg_compare.c |
+ | |
+ | Compare two floating point registers |
+ | |
+ | Copyright (C) 1992,1993,1994,1997 |
+ | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
+ | E-mail billm@suburbia.net |
+ | |
+ | |
+ +---------------------------------------------------------------------------*/
+
+/*---------------------------------------------------------------------------+
+ | compare() is the core FPU_REG comparison function |
+ +---------------------------------------------------------------------------*/
+
+#include "fpu_system.h"
+#include "exception.h"
+#include "fpu_emu.h"
+#include "control_w.h"
+#include "status_w.h"
+
+static int compare(FPU_REG const *b, int tagb)
+{
+ int diff, exp0, expb;
+ u_char st0_tag;
+ FPU_REG *st0_ptr;
+ FPU_REG x, y;
+ u_char st0_sign, signb = getsign(b);
+
+ st0_ptr = &st(0);
+ st0_tag = FPU_gettag0();
+ st0_sign = getsign(st0_ptr);
+
+ if (tagb == TAG_Special)
+ tagb = FPU_Special(b);
+ if (st0_tag == TAG_Special)
+ st0_tag = FPU_Special(st0_ptr);
+
+ if (((st0_tag != TAG_Valid) && (st0_tag != TW_Denormal))
+ || ((tagb != TAG_Valid) && (tagb != TW_Denormal))) {
+ if (st0_tag == TAG_Zero) {
+ if (tagb == TAG_Zero)
+ return COMP_A_eq_B;
+ if (tagb == TAG_Valid)
+ return ((signb ==
+ SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B);
+ if (tagb == TW_Denormal)
+ return ((signb ==
+ SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
+ | COMP_Denormal;
+ } else if (tagb == TAG_Zero) {
+ if (st0_tag == TAG_Valid)
+ return ((st0_sign ==
+ SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
+ if (st0_tag == TW_Denormal)
+ return ((st0_sign ==
+ SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
+ | COMP_Denormal;
+ }
+
+ if (st0_tag == TW_Infinity) {
+ if ((tagb == TAG_Valid) || (tagb == TAG_Zero))
+ return ((st0_sign ==
+ SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
+ else if (tagb == TW_Denormal)
+ return ((st0_sign ==
+ SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
+ | COMP_Denormal;
+ else if (tagb == TW_Infinity) {
+ /* The 80486 book says that infinities can be equal! */
+ return (st0_sign == signb) ? COMP_A_eq_B :
+ ((st0_sign ==
+ SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B);
+ }
+ /* Fall through to the NaN code */
+ } else if (tagb == TW_Infinity) {
+ if ((st0_tag == TAG_Valid) || (st0_tag == TAG_Zero))
+ return ((signb ==
+ SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B);
+ if (st0_tag == TW_Denormal)
+ return ((signb ==
+ SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
+ | COMP_Denormal;
+ /* Fall through to the NaN code */
+ }
+
+ /* The only possibility now should be that one of the arguments
+ is a NaN */
+ if ((st0_tag == TW_NaN) || (tagb == TW_NaN)) {
+ int signalling = 0, unsupported = 0;
+ if (st0_tag == TW_NaN) {
+ signalling =
+ (st0_ptr->sigh & 0xc0000000) == 0x80000000;
+ unsupported = !((exponent(st0_ptr) == EXP_OVER)
+ && (st0_ptr->
+ sigh & 0x80000000));
+ }
+ if (tagb == TW_NaN) {
+ signalling |=
+ (b->sigh & 0xc0000000) == 0x80000000;
+ unsupported |= !((exponent(b) == EXP_OVER)
+ && (b->sigh & 0x80000000));
+ }
+ if (signalling || unsupported)
+ return COMP_No_Comp | COMP_SNaN | COMP_NaN;
+ else
+ /* Neither is a signaling NaN */
+ return COMP_No_Comp | COMP_NaN;
+ }
+
+ EXCEPTION(EX_Invalid);
+ }
+
+ if (st0_sign != signb) {
+ return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
+ | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
+ COMP_Denormal : 0);
+ }
+
+ if ((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) {
+ FPU_to_exp16(st0_ptr, &x);
+ FPU_to_exp16(b, &y);
+ st0_ptr = &x;
+ b = &y;
+ exp0 = exponent16(st0_ptr);
+ expb = exponent16(b);
+ } else {
+ exp0 = exponent(st0_ptr);
+ expb = exponent(b);
+ }
+
+#ifdef PARANOID
+ if (!(st0_ptr->sigh & 0x80000000))
+ EXCEPTION(EX_Invalid);
+ if (!(b->sigh & 0x80000000))
+ EXCEPTION(EX_Invalid);
+#endif /* PARANOID */
+
+ diff = exp0 - expb;
+ if (diff == 0) {
+ diff = st0_ptr->sigh - b->sigh; /* Works only if ms bits are
+ identical */
+ if (diff == 0) {
+ diff = st0_ptr->sigl > b->sigl;
+ if (diff == 0)
+ diff = -(st0_ptr->sigl < b->sigl);
+ }
+ }
+
+ if (diff > 0) {
+ return ((st0_sign == SIGN_POS) ? COMP_A_gt_B : COMP_A_lt_B)
+ | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
+ COMP_Denormal : 0);
+ }
+ if (diff < 0) {
+ return ((st0_sign == SIGN_POS) ? COMP_A_lt_B : COMP_A_gt_B)
+ | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
+ COMP_Denormal : 0);
+ }
+
+ return COMP_A_eq_B
+ | (((st0_tag == TW_Denormal) || (tagb == TW_Denormal)) ?
+ COMP_Denormal : 0);
+
+}
+
+/* This function requires that st(0) is not empty */
+int FPU_compare_st_data(FPU_REG const *loaded_data, u_char loaded_tag)
+{
+ int f, c;
+
+ c = compare(loaded_data, loaded_tag);
+
+ if (c & COMP_NaN) {
+ EXCEPTION(EX_Invalid);
+ f = SW_C3 | SW_C2 | SW_C0;
+ } else
+ switch (c & 7) {
+ case COMP_A_lt_B:
+ f = SW_C0;
+ break;
+ case COMP_A_eq_B:
+ f = SW_C3;
+ break;
+ case COMP_A_gt_B:
+ f = 0;
+ break;
+ case COMP_No_Comp:
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+ default:
+#ifdef PARANOID
+ EXCEPTION(EX_INTERNAL | 0x121);
+#endif /* PARANOID */
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+ }
+ setcc(f);
+ if (c & COMP_Denormal) {
+ return denormal_operand() < 0;
+ }
+ return 0;
+}
+
+static int compare_st_st(int nr)
+{
+ int f, c;
+ FPU_REG *st_ptr;
+
+ if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+ setcc(SW_C3 | SW_C2 | SW_C0);
+ /* Stack fault */
+ EXCEPTION(EX_StackUnder);
+ return !(control_word & CW_Invalid);
+ }
+
+ st_ptr = &st(nr);
+ c = compare(st_ptr, FPU_gettagi(nr));
+ if (c & COMP_NaN) {
+ setcc(SW_C3 | SW_C2 | SW_C0);
+ EXCEPTION(EX_Invalid);
+ return !(control_word & CW_Invalid);
+ } else
+ switch (c & 7) {
+ case COMP_A_lt_B:
+ f = SW_C0;
+ break;
+ case COMP_A_eq_B:
+ f = SW_C3;
+ break;
+ case COMP_A_gt_B:
+ f = 0;
+ break;
+ case COMP_No_Comp:
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+ default:
+#ifdef PARANOID
+ EXCEPTION(EX_INTERNAL | 0x122);
+#endif /* PARANOID */
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+ }
+ setcc(f);
+ if (c & COMP_Denormal) {
+ return denormal_operand() < 0;
+ }
+ return 0;
+}
+
+static int compare_i_st_st(int nr)
+{
+ int f, c;
+ FPU_REG *st_ptr;
+
+ if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+ FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+ /* Stack fault */
+ EXCEPTION(EX_StackUnder);
+ return !(control_word & CW_Invalid);
+ }
+
+ partial_status &= ~SW_C0;
+ st_ptr = &st(nr);
+ c = compare(st_ptr, FPU_gettagi(nr));
+ if (c & COMP_NaN) {
+ FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+ EXCEPTION(EX_Invalid);
+ return !(control_word & CW_Invalid);
+ }
+
+ switch (c & 7) {
+ case COMP_A_lt_B:
+ f = X86_EFLAGS_CF;
+ break;
+ case COMP_A_eq_B:
+ f = X86_EFLAGS_ZF;
+ break;
+ case COMP_A_gt_B:
+ f = 0;
+ break;
+ case COMP_No_Comp:
+ f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF;
+ break;
+ default:
+#ifdef PARANOID
+ EXCEPTION(EX_INTERNAL | 0x122);
+#endif /* PARANOID */
+ f = 0;
+ break;
+ }
+ FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f;
+ if (c & COMP_Denormal) {
+ return denormal_operand() < 0;
+ }
+ return 0;
+}
+
+static int compare_u_st_st(int nr)
+{
+ int f = 0, c;
+ FPU_REG *st_ptr;
+
+ if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+ setcc(SW_C3 | SW_C2 | SW_C0);
+ /* Stack fault */
+ EXCEPTION(EX_StackUnder);
+ return !(control_word & CW_Invalid);
+ }
+
+ st_ptr = &st(nr);
+ c = compare(st_ptr, FPU_gettagi(nr));
+ if (c & COMP_NaN) {
+ setcc(SW_C3 | SW_C2 | SW_C0);
+ if (c & COMP_SNaN) { /* This is the only difference between
+ un-ordered and ordinary comparisons */
+ EXCEPTION(EX_Invalid);
+ return !(control_word & CW_Invalid);
+ }
+ return 0;
+ } else
+ switch (c & 7) {
+ case COMP_A_lt_B:
+ f = SW_C0;
+ break;
+ case COMP_A_eq_B:
+ f = SW_C3;
+ break;
+ case COMP_A_gt_B:
+ f = 0;
+ break;
+ case COMP_No_Comp:
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+#ifdef PARANOID
+ default:
+ EXCEPTION(EX_INTERNAL | 0x123);
+ f = SW_C3 | SW_C2 | SW_C0;
+ break;
+#endif /* PARANOID */
+ }
+ setcc(f);
+ if (c & COMP_Denormal) {
+ return denormal_operand() < 0;
+ }
+ return 0;
+}
+
+static int compare_ui_st_st(int nr)
+{
+ int f = 0, c;
+ FPU_REG *st_ptr;
+
+ if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+ FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+ /* Stack fault */
+ EXCEPTION(EX_StackUnder);
+ return !(control_word & CW_Invalid);
+ }
+
+ partial_status &= ~SW_C0;
+ st_ptr = &st(nr);
+ c = compare(st_ptr, FPU_gettagi(nr));
+ if (c & COMP_NaN) {
+ FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+ if (c & COMP_SNaN) { /* This is the only difference between
+ un-ordered and ordinary comparisons */
+ EXCEPTION(EX_Invalid);
+ return !(control_word & CW_Invalid);
+ }
+ return 0;
+ }
+
+ switch (c & 7) {
+ case COMP_A_lt_B:
+ f = X86_EFLAGS_CF;
+ break;
+ case COMP_A_eq_B:
+ f = X86_EFLAGS_ZF;
+ break;
+ case COMP_A_gt_B:
+ f = 0;
+ break;
+ case COMP_No_Comp:
+ f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF;
+ break;
+#ifdef PARANOID
+ default:
+ EXCEPTION(EX_INTERNAL | 0x123);
+ f = 0;
+ break;
+#endif /* PARANOID */
+ }
+ FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f;
+ if (c & COMP_Denormal) {
+ return denormal_operand() < 0;
+ }
+ return 0;
+}
+
+/*---------------------------------------------------------------------------*/
+
+void fcom_st(void)
+{
+ /* fcom st(i) */
+ compare_st_st(FPU_rm);
+}
+
+void fcompst(void)
+{
+ /* fcomp st(i) */
+ if (!compare_st_st(FPU_rm))
+ FPU_pop();
+}
+
+void fcompp(void)
+{
+ /* fcompp */
+ if (FPU_rm != 1) {
+ FPU_illegal();
+ return;
+ }
+ if (!compare_st_st(1))
+ poppop();
+}
+
+void fucom_(void)
+{
+ /* fucom st(i) */
+ compare_u_st_st(FPU_rm);
+
+}
+
+void fucomp(void)
+{
+ /* fucomp st(i) */
+ if (!compare_u_st_st(FPU_rm))
+ FPU_pop();
+}
+
+void fucompp(void)
+{
+ /* fucompp */
+ if (FPU_rm == 1) {
+ if (!compare_u_st_st(1))
+ poppop();
+ } else
+ FPU_illegal();
+}
+
+/* P6+ compare-to-EFLAGS ops */
+
+void fcomi_(void)
+{
+ /* fcomi st(i) */
+ compare_i_st_st(FPU_rm);
+}
+
+void fcomip(void)
+{
+ /* fcomip st(i) */
+ if (!compare_i_st_st(FPU_rm))
+ FPU_pop();
+}
+
+void fucomi_(void)
+{
+ /* fucomi st(i) */
+ compare_ui_st_st(FPU_rm);
+}
+
+void fucomip(void)
+{
+ /* fucomip st(i) */
+ if (!compare_ui_st_st(FPU_rm))
+ FPU_pop();
+}
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