243 lines
6.6 KiB
C
243 lines
6.6 KiB
C
/*
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* x86 condition code helpers
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*
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* Copyright (c) 2008 Fabrice Bellard
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, see <http://www.gnu.org/licenses/>.
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*/
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#define DATA_BITS (1 << (3 + SHIFT))
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#if DATA_BITS == 8
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#define SUFFIX b
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#define DATA_TYPE uint8_t
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#elif DATA_BITS == 16
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#define SUFFIX w
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#define DATA_TYPE uint16_t
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#elif DATA_BITS == 32
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#define SUFFIX l
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#define DATA_TYPE uint32_t
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#elif DATA_BITS == 64
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#define SUFFIX q
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#define DATA_TYPE uint64_t
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#else
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#error unhandled operand size
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#endif
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#define SIGN_MASK (((DATA_TYPE)1) << (DATA_BITS - 1))
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/* dynamic flags computation */
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static int glue(compute_all_add, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src2 = dst - src1;
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cf = dst < src1;
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & CC_A;
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = lshift((src1 ^ src2 ^ -1) & (src1 ^ dst), 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_add, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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return dst < src1;
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}
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static int glue(compute_all_adc, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1,
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DATA_TYPE src3)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src2 = dst - src1 - src3;
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cf = (src3 ? dst <= src1 : dst < src1);
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & 0x10;
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zf = (dst == 0) << 6;
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sf = lshift(dst, 8 - DATA_BITS) & 0x80;
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of = lshift((src1 ^ src2 ^ -1) & (src1 ^ dst), 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_adc, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1,
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DATA_TYPE src3)
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{
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return src3 ? dst <= src1 : dst < src1;
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}
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static int glue(compute_all_sub, SUFFIX)(DATA_TYPE dst, DATA_TYPE src2)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src1 = dst + src2;
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cf = src1 < src2;
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & CC_A;
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = lshift((src1 ^ src2) & (src1 ^ dst), 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_sub, SUFFIX)(DATA_TYPE dst, DATA_TYPE src2)
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{
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DATA_TYPE src1 = dst + src2;
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return src1 < src2;
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}
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static int glue(compute_all_sbb, SUFFIX)(DATA_TYPE dst, DATA_TYPE src2,
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DATA_TYPE src3)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src1 = dst + src2 + src3;
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cf = (src3 ? src1 <= src2 : src1 < src2);
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & 0x10;
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zf = (dst == 0) << 6;
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sf = lshift(dst, 8 - DATA_BITS) & 0x80;
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of = lshift((src1 ^ src2) & (src1 ^ dst), 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_sbb, SUFFIX)(DATA_TYPE dst, DATA_TYPE src2,
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DATA_TYPE src3)
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{
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DATA_TYPE src1 = dst + src2 + src3;
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return (src3 ? src1 <= src2 : src1 < src2);
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}
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static int glue(compute_all_logic, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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cf = 0;
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pf = parity_table[(uint8_t)dst];
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af = 0;
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = 0;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_all_inc, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src2;
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cf = src1;
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src1 = dst - 1;
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src2 = 1;
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & CC_A;
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = (dst == SIGN_MASK) * CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_all_dec, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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DATA_TYPE src2;
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cf = src1;
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src1 = dst + 1;
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src2 = 1;
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pf = parity_table[(uint8_t)dst];
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af = (dst ^ src1 ^ src2) & CC_A;
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = (dst == SIGN_MASK - 1) * CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_all_shl, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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cf = (src1 >> (DATA_BITS - 1)) & CC_C;
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pf = parity_table[(uint8_t)dst];
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af = 0; /* undefined */
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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/* of is defined iff shift count == 1 */
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of = lshift(src1 ^ dst, 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_shl, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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return (src1 >> (DATA_BITS - 1)) & CC_C;
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}
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static int glue(compute_all_sar, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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cf = src1 & 1;
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pf = parity_table[(uint8_t)dst];
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af = 0; /* undefined */
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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/* of is defined iff shift count == 1 */
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of = lshift(src1 ^ dst, 12 - DATA_BITS) & CC_O;
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return cf | pf | af | zf | sf | of;
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}
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/* NOTE: we compute the flags like the P4. On olders CPUs, only OF and
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CF are modified and it is slower to do that. Note as well that we
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don't truncate SRC1 for computing carry to DATA_TYPE. */
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static int glue(compute_all_mul, SUFFIX)(DATA_TYPE dst, target_long src1)
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{
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int cf, pf, af, zf, sf, of;
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cf = (src1 != 0);
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pf = parity_table[(uint8_t)dst];
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af = 0; /* undefined */
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = cf * CC_O;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_all_bmilg, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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int cf, pf, af, zf, sf, of;
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cf = (src1 == 0);
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pf = 0; /* undefined */
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af = 0; /* undefined */
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zf = (dst == 0) * CC_Z;
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sf = lshift(dst, 8 - DATA_BITS) & CC_S;
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of = 0;
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return cf | pf | af | zf | sf | of;
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}
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static int glue(compute_c_bmilg, SUFFIX)(DATA_TYPE dst, DATA_TYPE src1)
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{
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return src1 == 0;
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}
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#undef DATA_BITS
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#undef SIGN_MASK
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#undef DATA_TYPE
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#undef DATA_MASK
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#undef SUFFIX
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