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