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-rw-r--r--arch/i386/math-emu/reg_constant.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/arch/i386/math-emu/reg_constant.c b/arch/i386/math-emu/reg_constant.c
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+++ b/arch/i386/math-emu/reg_constant.c
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+/*---------------------------------------------------------------------------+
+ | reg_constant.c |
+ | |
+ | All of the constant FPU_REGs |
+ | |
+ | 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 "fpu_emu.h"
+#include "status_w.h"
+#include "reg_constant.h"
+#include "control_w.h"
+
+
+#define MAKE_REG(s,e,l,h) { l, h, \
+ ((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) }
+
+FPU_REG const CONST_1 = MAKE_REG(POS, 0, 0x00000000, 0x80000000);
+#if 0
+FPU_REG const CONST_2 = MAKE_REG(POS, 1, 0x00000000, 0x80000000);
+FPU_REG const CONST_HALF = MAKE_REG(POS, -1, 0x00000000, 0x80000000);
+#endif /* 0 */
+static FPU_REG const CONST_L2T = MAKE_REG(POS, 1, 0xcd1b8afe, 0xd49a784b);
+static FPU_REG const CONST_L2E = MAKE_REG(POS, 0, 0x5c17f0bc, 0xb8aa3b29);
+FPU_REG const CONST_PI = MAKE_REG(POS, 1, 0x2168c235, 0xc90fdaa2);
+FPU_REG const CONST_PI2 = MAKE_REG(POS, 0, 0x2168c235, 0xc90fdaa2);
+FPU_REG const CONST_PI4 = MAKE_REG(POS, -1, 0x2168c235, 0xc90fdaa2);
+static FPU_REG const CONST_LG2 = MAKE_REG(POS, -2, 0xfbcff799, 0x9a209a84);
+static FPU_REG const CONST_LN2 = MAKE_REG(POS, -1, 0xd1cf79ac, 0xb17217f7);
+
+/* Extra bits to take pi/2 to more than 128 bits precision. */
+FPU_REG const CONST_PI2extra = MAKE_REG(NEG, -66,
+ 0xfc8f8cbb, 0xece675d1);
+
+/* Only the sign (and tag) is used in internal zeroes */
+FPU_REG const CONST_Z = MAKE_REG(POS, EXP_UNDER, 0x0, 0x0);
+
+/* Only the sign and significand (and tag) are used in internal NaNs */
+/* The 80486 never generates one of these
+FPU_REG const CONST_SNAN = MAKE_REG(POS, EXP_OVER, 0x00000001, 0x80000000);
+ */
+/* This is the real indefinite QNaN */
+FPU_REG const CONST_QNaN = MAKE_REG(NEG, EXP_OVER, 0x00000000, 0xC0000000);
+
+/* Only the sign (and tag) is used in internal infinities */
+FPU_REG const CONST_INF = MAKE_REG(POS, EXP_OVER, 0x00000000, 0x80000000);
+
+
+static void fld_const(FPU_REG const *c, int adj, u_char tag)
+{
+ FPU_REG *st_new_ptr;
+
+ if ( STACK_OVERFLOW )
+ {
+ FPU_stack_overflow();
+ return;
+ }
+ push();
+ reg_copy(c, st_new_ptr);
+ st_new_ptr->sigl += adj; /* For all our fldxxx constants, we don't need to
+ borrow or carry. */
+ FPU_settag0(tag);
+ clear_C1();
+}
+
+/* A fast way to find out whether x is one of RC_DOWN or RC_CHOP
+ (and not one of RC_RND or RC_UP).
+ */
+#define DOWN_OR_CHOP(x) (x & RC_DOWN)
+
+static void fld1(int rc)
+{
+ fld_const(&CONST_1, 0, TAG_Valid);
+}
+
+static void fldl2t(int rc)
+{
+ fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0, TAG_Valid);
+}
+
+static void fldl2e(int rc)
+{
+ fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
+}
+
+static void fldpi(int rc)
+{
+ fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
+}
+
+static void fldlg2(int rc)
+{
+ fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
+}
+
+static void fldln2(int rc)
+{
+ fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid);
+}
+
+static void fldz(int rc)
+{
+ fld_const(&CONST_Z, 0, TAG_Zero);
+}
+
+typedef void (*FUNC_RC)(int);
+
+static FUNC_RC constants_table[] = {
+ fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC)FPU_illegal
+};
+
+void fconst(void)
+{
+ (constants_table[FPU_rm])(control_word & CW_RC);
+}