diff options
Diffstat (limited to 'arch/x86/math-emu/reg_constant.c')
| -rw-r--r-- | arch/x86/math-emu/reg_constant.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/arch/x86/math-emu/reg_constant.c b/arch/x86/math-emu/reg_constant.c new file mode 100644 index 000000000..742619e94 --- /dev/null +++ b/arch/x86/math-emu/reg_constant.c @@ -0,0 +1,118 @@ +// SPDX-License-Identifier: GPL-2.0 +/*---------------------------------------------------------------------------+ + | 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, \ + (u16)((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); +} |