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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | /*---------------------------------------------------------------------------+ | 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); } |