1/*---------------------------------------------------------------------------+ 2 | reg_constant.c | 3 | | 4 | All of the constant FPU_REGs | 5 | | 6 | Copyright (C) 1992,1993,1994,1997 | 7 | W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | 8 | Australia. E-mail billm@suburbia.net | 9 | | 10 | | 11 +---------------------------------------------------------------------------*/ 12 13#include "fpu_system.h" 14#include "fpu_emu.h" 15#include "status_w.h" 16#include "reg_constant.h" 17#include "control_w.h" 18 19 20#define MAKE_REG(s,e,l,h) { l, h, \ 21 ((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) } 22 23FPU_REG const CONST_1 = MAKE_REG(POS, 0, 0x00000000, 0x80000000); 24static FPU_REG const CONST_L2T = MAKE_REG(POS, 1, 0xcd1b8afe, 0xd49a784b); 25static FPU_REG const CONST_L2E = MAKE_REG(POS, 0, 0x5c17f0bc, 0xb8aa3b29); 26FPU_REG const CONST_PI = MAKE_REG(POS, 1, 0x2168c235, 0xc90fdaa2); 27FPU_REG const CONST_PI2 = MAKE_REG(POS, 0, 0x2168c235, 0xc90fdaa2); 28FPU_REG const CONST_PI4 = MAKE_REG(POS, -1, 0x2168c235, 0xc90fdaa2); 29static FPU_REG const CONST_LG2 = MAKE_REG(POS, -2, 0xfbcff799, 0x9a209a84); 30static FPU_REG const CONST_LN2 = MAKE_REG(POS, -1, 0xd1cf79ac, 0xb17217f7); 31 32/* Extra bits to take pi/2 to more than 128 bits precision. */ 33FPU_REG const CONST_PI2extra = MAKE_REG(NEG, -66, 34 0xfc8f8cbb, 0xece675d1); 35 36/* Only the sign (and tag) is used in internal zeroes */ 37FPU_REG const CONST_Z = MAKE_REG(POS, EXP_UNDER, 0x0, 0x0); 38 39/* Only the sign and significand (and tag) are used in internal NaNs */ 40/* The 80486 never generates one of these 41FPU_REG const CONST_SNAN = MAKE_REG(POS, EXP_OVER, 0x00000001, 0x80000000); 42 */ 43/* This is the real indefinite QNaN */ 44FPU_REG const CONST_QNaN = MAKE_REG(NEG, EXP_OVER, 0x00000000, 0xC0000000); 45 46/* Only the sign (and tag) is used in internal infinities */ 47FPU_REG const CONST_INF = MAKE_REG(POS, EXP_OVER, 0x00000000, 0x80000000); 48 49 50static void fld_const(FPU_REG const *c, int adj, u_char tag) 51{ 52 FPU_REG *st_new_ptr; 53 54 if ( STACK_OVERFLOW ) 55 { 56 FPU_stack_overflow(); 57 return; 58 } 59 push(); 60 reg_copy(c, st_new_ptr); 61 st_new_ptr->sigl += adj; /* For all our fldxxx constants, we don't need to 62 borrow or carry. */ 63 FPU_settag0(tag); 64 clear_C1(); 65} 66 67/* A fast way to find out whether x is one of RC_DOWN or RC_CHOP 68 (and not one of RC_RND or RC_UP). 69 */ 70#define DOWN_OR_CHOP(x) (x & RC_DOWN) 71 72static void fld1(int rc) 73{ 74 fld_const(&CONST_1, 0, TAG_Valid); 75} 76 77static void fldl2t(int rc) 78{ 79 fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0, TAG_Valid); 80} 81 82static void fldl2e(int rc) 83{ 84 fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); 85} 86 87static void fldpi(int rc) 88{ 89 fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); 90} 91 92static void fldlg2(int rc) 93{ 94 fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); 95} 96 97static void fldln2(int rc) 98{ 99 fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); 100} 101 102static void fldz(int rc) 103{ 104 fld_const(&CONST_Z, 0, TAG_Zero); 105} 106 107typedef void (*FUNC_RC)(int); 108 109static FUNC_RC constants_table[] = { 110 fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC)FPU_illegal 111}; 112 113void fconst(void) 114{ 115 (constants_table[FPU_rm])(control_word & CW_RC); 116} 117