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118 lines
3.8 KiB
118 lines
3.8 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/*---------------------------------------------------------------------------+ |
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| reg_constant.c | |
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| All of the constant FPU_REGs | |
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| Copyright (C) 1992,1993,1994,1997 | |
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| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, | |
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| Australia. E-mail [email protected] | |
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+---------------------------------------------------------------------------*/ |
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#include "fpu_system.h" |
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#include "fpu_emu.h" |
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#include "status_w.h" |
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#include "reg_constant.h" |
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#include "control_w.h" |
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#define MAKE_REG(s, e, l, h) { l, h, \ |
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(u16)((EXTENDED_Ebias+(e)) | ((SIGN_##s != 0)*0x8000)) } |
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FPU_REG const CONST_1 = MAKE_REG(POS, 0, 0x00000000, 0x80000000); |
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#if 0 |
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FPU_REG const CONST_2 = MAKE_REG(POS, 1, 0x00000000, 0x80000000); |
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FPU_REG const CONST_HALF = MAKE_REG(POS, -1, 0x00000000, 0x80000000); |
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#endif /* 0 */ |
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static FPU_REG const CONST_L2T = MAKE_REG(POS, 1, 0xcd1b8afe, 0xd49a784b); |
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static FPU_REG const CONST_L2E = MAKE_REG(POS, 0, 0x5c17f0bc, 0xb8aa3b29); |
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FPU_REG const CONST_PI = MAKE_REG(POS, 1, 0x2168c235, 0xc90fdaa2); |
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FPU_REG const CONST_PI2 = MAKE_REG(POS, 0, 0x2168c235, 0xc90fdaa2); |
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FPU_REG const CONST_PI4 = MAKE_REG(POS, -1, 0x2168c235, 0xc90fdaa2); |
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static FPU_REG const CONST_LG2 = MAKE_REG(POS, -2, 0xfbcff799, 0x9a209a84); |
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static FPU_REG const CONST_LN2 = MAKE_REG(POS, -1, 0xd1cf79ac, 0xb17217f7); |
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/* Extra bits to take pi/2 to more than 128 bits precision. */ |
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FPU_REG const CONST_PI2extra = MAKE_REG(NEG, -66, |
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0xfc8f8cbb, 0xece675d1); |
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/* Only the sign (and tag) is used in internal zeroes */ |
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FPU_REG const CONST_Z = MAKE_REG(POS, EXP_UNDER, 0x0, 0x0); |
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/* Only the sign and significand (and tag) are used in internal NaNs */ |
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/* The 80486 never generates one of these |
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FPU_REG const CONST_SNAN = MAKE_REG(POS, EXP_OVER, 0x00000001, 0x80000000); |
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*/ |
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/* This is the real indefinite QNaN */ |
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FPU_REG const CONST_QNaN = MAKE_REG(NEG, EXP_OVER, 0x00000000, 0xC0000000); |
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/* Only the sign (and tag) is used in internal infinities */ |
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FPU_REG const CONST_INF = MAKE_REG(POS, EXP_OVER, 0x00000000, 0x80000000); |
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static void fld_const(FPU_REG const * c, int adj, u_char tag) |
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{ |
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FPU_REG *st_new_ptr; |
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if (STACK_OVERFLOW) { |
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FPU_stack_overflow(); |
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return; |
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} |
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push(); |
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reg_copy(c, st_new_ptr); |
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st_new_ptr->sigl += adj; /* For all our fldxxx constants, we don't need to |
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borrow or carry. */ |
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FPU_settag0(tag); |
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clear_C1(); |
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} |
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/* A fast way to find out whether x is one of RC_DOWN or RC_CHOP |
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(and not one of RC_RND or RC_UP). |
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*/ |
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#define DOWN_OR_CHOP(x) (x & RC_DOWN) |
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static void fld1(int rc) |
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{ |
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fld_const(&CONST_1, 0, TAG_Valid); |
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} |
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static void fldl2t(int rc) |
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{ |
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fld_const(&CONST_L2T, (rc == RC_UP) ? 1 : 0, TAG_Valid); |
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} |
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static void fldl2e(int rc) |
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{ |
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fld_const(&CONST_L2E, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
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} |
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static void fldpi(int rc) |
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{ |
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fld_const(&CONST_PI, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
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} |
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static void fldlg2(int rc) |
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{ |
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fld_const(&CONST_LG2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
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} |
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static void fldln2(int rc) |
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{ |
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fld_const(&CONST_LN2, DOWN_OR_CHOP(rc) ? -1 : 0, TAG_Valid); |
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} |
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static void fldz(int rc) |
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{ |
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fld_const(&CONST_Z, 0, TAG_Zero); |
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} |
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typedef void (*FUNC_RC) (int); |
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static FUNC_RC constants_table[] = { |
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fld1, fldl2t, fldl2e, fldpi, fldlg2, fldln2, fldz, (FUNC_RC) FPU_illegal |
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}; |
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void fconst(void) |
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{ |
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(constants_table[FPU_rm]) (control_word & CW_RC); |
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}
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