target-i386: Implement tzcnt and fix lzcnt
We weren't computing flags for lzcnt at all. At the same time, adjust the implementation of bsf/bsr to avoid the local branch, using movcond instead. Signed-off-by: Richard Henderson <rth@twiddle.net>
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@ -195,9 +195,8 @@ DEF_HELPER_3(frstor, void, env, tl, int)
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DEF_HELPER_3(fxsave, void, env, tl, int)
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DEF_HELPER_3(fxrstor, void, env, tl, int)
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DEF_HELPER_FLAGS_1(bsf, TCG_CALL_NO_RWG_SE, tl, tl)
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DEF_HELPER_FLAGS_1(bsr, TCG_CALL_NO_RWG_SE, tl, tl)
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DEF_HELPER_FLAGS_2(lzcnt, TCG_CALL_NO_RWG_SE, tl, tl, int)
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DEF_HELPER_FLAGS_1(clz, TCG_CALL_NO_RWG_SE, tl, tl)
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DEF_HELPER_FLAGS_1(ctz, TCG_CALL_NO_RWG_SE, tl, tl)
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DEF_HELPER_FLAGS_2(pdep, TCG_CALL_NO_RWG_SE, tl, tl, tl)
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DEF_HELPER_FLAGS_2(pext, TCG_CALL_NO_RWG_SE, tl, tl, tl)
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@ -456,19 +456,14 @@ void helper_idivq_EAX(CPUX86State *env, target_ulong t0)
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#endif
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/* bit operations */
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target_ulong helper_bsf(target_ulong t0)
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target_ulong helper_ctz(target_ulong t0)
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{
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return ctztl(t0);
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}
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target_ulong helper_lzcnt(target_ulong t0, int wordsize)
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target_ulong helper_clz(target_ulong t0)
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{
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return clztl(t0) - (TARGET_LONG_BITS - wordsize);
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}
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target_ulong helper_bsr(target_ulong t0)
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{
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return clztl(t0) ^ (TARGET_LONG_BITS - 1);
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return clztl(t0);
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}
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target_ulong helper_pdep(target_ulong src, target_ulong mask)
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@ -7157,46 +7157,58 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
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tcg_gen_movi_tl(cpu_cc_dst, 0);
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}
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break;
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case 0x1bc: /* bsf */
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case 0x1bd: /* bsr */
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{
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int label1;
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TCGv t0;
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case 0x1bc: /* bsf / tzcnt */
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case 0x1bd: /* bsr / lzcnt */
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ot = dflag + OT_WORD;
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modrm = cpu_ldub_code(env, s->pc++);
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reg = ((modrm >> 3) & 7) | rex_r;
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gen_ldst_modrm(env, s,modrm, ot, OR_TMP0, 0);
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gen_ldst_modrm(env, s, modrm, ot, OR_TMP0, 0);
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gen_extu(ot, cpu_T[0]);
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t0 = tcg_temp_local_new();
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tcg_gen_mov_tl(t0, cpu_T[0]);
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if ((b & 1) && (prefixes & PREFIX_REPZ) &&
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(s->cpuid_ext3_features & CPUID_EXT3_ABM)) {
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switch(ot) {
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case OT_WORD: gen_helper_lzcnt(cpu_T[0], t0,
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tcg_const_i32(16)); break;
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case OT_LONG: gen_helper_lzcnt(cpu_T[0], t0,
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tcg_const_i32(32)); break;
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case OT_QUAD: gen_helper_lzcnt(cpu_T[0], t0,
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tcg_const_i32(64)); break;
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}
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gen_op_mov_reg_T0(ot, reg);
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} else {
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label1 = gen_new_label();
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tcg_gen_movi_tl(cpu_cc_dst, 0);
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tcg_gen_brcondi_tl(TCG_COND_EQ, t0, 0, label1);
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/* Note that lzcnt and tzcnt are in different extensions. */
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if ((prefixes & PREFIX_REPZ)
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&& (b & 1
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? s->cpuid_ext3_features & CPUID_EXT3_ABM
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: s->cpuid_7_0_ebx_features & CPUID_7_0_EBX_BMI1)) {
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int size = 8 << ot;
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tcg_gen_mov_tl(cpu_cc_src, cpu_T[0]);
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if (b & 1) {
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gen_helper_bsr(cpu_T[0], t0);
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/* For lzcnt, reduce the target_ulong result by the
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number of zeros that we expect to find at the top. */
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gen_helper_clz(cpu_T[0], cpu_T[0]);
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tcg_gen_subi_tl(cpu_T[0], cpu_T[0], TARGET_LONG_BITS - size);
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} else {
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gen_helper_bsf(cpu_T[0], t0);
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/* For tzcnt, a zero input must return the operand size:
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force all bits outside the operand size to 1. */
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target_ulong mask = (target_ulong)-2 << (size - 1);
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tcg_gen_ori_tl(cpu_T[0], cpu_T[0], mask);
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gen_helper_ctz(cpu_T[0], cpu_T[0]);
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}
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/* For lzcnt/tzcnt, C and Z bits are defined and are
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related to the result. */
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gen_op_update1_cc();
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set_cc_op(s, CC_OP_BMILGB + ot);
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} else {
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/* For bsr/bsf, only the Z bit is defined and it is related
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to the input and not the result. */
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tcg_gen_mov_tl(cpu_cc_dst, cpu_T[0]);
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set_cc_op(s, CC_OP_LOGICB + ot);
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if (b & 1) {
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/* For bsr, return the bit index of the first 1 bit,
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not the count of leading zeros. */
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gen_helper_clz(cpu_T[0], cpu_T[0]);
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tcg_gen_xori_tl(cpu_T[0], cpu_T[0], TARGET_LONG_BITS - 1);
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} else {
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gen_helper_ctz(cpu_T[0], cpu_T[0]);
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}
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/* ??? The manual says that the output is undefined when the
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input is zero, but real hardware leaves it unchanged, and
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real programs appear to depend on that. */
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tcg_gen_movi_tl(cpu_tmp0, 0);
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tcg_gen_movcond_tl(TCG_COND_EQ, cpu_T[0], cpu_cc_dst, cpu_tmp0,
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cpu_regs[reg], cpu_T[0]);
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}
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gen_op_mov_reg_T0(ot, reg);
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tcg_gen_movi_tl(cpu_cc_dst, 1);
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gen_set_label(label1);
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set_cc_op(s, CC_OP_LOGICB + ot);
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}
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tcg_temp_free(t0);
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}
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break;
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/************************/
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/* bcd */
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