From 5baf5641cc82fe18e98c1063d8682be9cdcae85c Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 19 Oct 2023 23:14:34 +0200 Subject: [PATCH] target/i386: rename zext0/zext2 and make them closer to the manual X86_SPECIAL_ZExtOp0 and X86_SPECIAL_ZExtOp2 are poorly named; they are a hack that is needed by scalar insertion and extraction instructions, and not really related to zero extension: for PEXTR the zero extension is done by the generation functions, for PINSR the high bits are not used at all and in fact are *not* filled with zeroes when loaded into s->T1. Rename the values to match the effect described in the manual, and explain better in the comments. Reviewed-by: Richard Henderson Signed-off-by: Paolo Bonzini --- target/i386/tcg/decode-new.c.inc | 16 ++++++++-------- target/i386/tcg/decode-new.h | 17 +++++++++++++---- 2 files changed, 21 insertions(+), 12 deletions(-) diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc index 5eb2e9d022..00fdb24385 100644 --- a/target/i386/tcg/decode-new.c.inc +++ b/target/i386/tcg/decode-new.c.inc @@ -153,8 +153,8 @@ #define xchg .special = X86_SPECIAL_Locked, #define lock .special = X86_SPECIAL_HasLock, #define mmx .special = X86_SPECIAL_MMX, -#define zext0 .special = X86_SPECIAL_ZExtOp0, -#define zext2 .special = X86_SPECIAL_ZExtOp2, +#define op0_Rd .special = X86_SPECIAL_Op0_Rd, +#define op2_Ry .special = X86_SPECIAL_Op2_Ry, #define avx_movx .special = X86_SPECIAL_AVXExtMov, #define vex1 .vex_class = 1, @@ -632,13 +632,13 @@ static const X86OpEntry opcodes_0F3A[256] = { [0x05] = X86_OP_ENTRY3(VPERMILPD_i, V,x, W,x, I,b, vex6 chk(W0) cpuid(AVX) p_66), [0x06] = X86_OP_ENTRY4(VPERM2x128, V,qq, H,qq, W,qq, vex6 chk(W0) cpuid(AVX) p_66), - [0x14] = X86_OP_ENTRY3(PEXTRB, E,b, V,dq, I,b, vex5 cpuid(SSE41) zext0 p_66), - [0x15] = X86_OP_ENTRY3(PEXTRW, E,w, V,dq, I,b, vex5 cpuid(SSE41) zext0 p_66), + [0x14] = X86_OP_ENTRY3(PEXTRB, E,b, V,dq, I,b, vex5 cpuid(SSE41) op0_Rd p_66), + [0x15] = X86_OP_ENTRY3(PEXTRW, E,w, V,dq, I,b, vex5 cpuid(SSE41) op0_Rd p_66), [0x16] = X86_OP_ENTRY3(PEXTR, E,y, V,dq, I,b, vex5 cpuid(SSE41) p_66), [0x17] = X86_OP_ENTRY3(VEXTRACTPS, E,d, V,dq, I,b, vex5 cpuid(SSE41) p_66), [0x1d] = X86_OP_ENTRY3(VCVTPS2PH, W,xh, V,x, I,b, vex11 chk(W0) cpuid(F16C) p_66), - [0x20] = X86_OP_ENTRY4(PINSRB, V,dq, H,dq, E,b, vex5 cpuid(SSE41) zext2 p_66), + [0x20] = X86_OP_ENTRY4(PINSRB, V,dq, H,dq, E,b, vex5 cpuid(SSE41) op2_Ry p_66), [0x21] = X86_OP_GROUP0(VINSERTPS), [0x22] = X86_OP_ENTRY4(PINSR, V,dq, H,dq, E,y, vex5 cpuid(SSE41) p_66), @@ -1883,17 +1883,17 @@ static void disas_insn_new(DisasContext *s, CPUState *cpu, int b) case X86_SPECIAL_HasLock: break; - case X86_SPECIAL_ZExtOp0: + case X86_SPECIAL_Op0_Rd: assert(decode.op[0].unit == X86_OP_INT); if (!decode.op[0].has_ea) { decode.op[0].ot = MO_32; } break; - case X86_SPECIAL_ZExtOp2: + case X86_SPECIAL_Op2_Ry: assert(decode.op[2].unit == X86_OP_INT); if (!decode.op[2].has_ea) { - decode.op[2].ot = MO_32; + decode.op[2].ot = s->dflag == MO_16 ? MO_32 : s->dflag; } break; diff --git a/target/i386/tcg/decode-new.h b/target/i386/tcg/decode-new.h index 611bfddd95..b253f7457a 100644 --- a/target/i386/tcg/decode-new.h +++ b/target/i386/tcg/decode-new.h @@ -165,11 +165,20 @@ typedef enum X86InsnSpecial { X86_SPECIAL_Locked, /* - * Register operand 0/2 is zero extended to 32 bits. Rd/Mb or Rd/Mw - * in the manual. + * Rd/Mb or Rd/Mw in the manual: register operand 0 is treated as 32 bits + * (and writeback zero-extends it to 64 bits if applicable). PREFIX_DATA + * does not trigger 16-bit writeback and, as a side effect, high-byte + * registers are never used. */ - X86_SPECIAL_ZExtOp0, - X86_SPECIAL_ZExtOp2, + X86_SPECIAL_Op0_Rd, + + /* + * Ry/Mb in the manual (PINSRB). However, the high bits are never used by + * the instruction in either the register or memory cases; the *real* effect + * of this modifier is that high-byte registers are never used, even without + * a REX prefix. Therefore, PINSRW does not need it despite having Ry/Mw. + */ + X86_SPECIAL_Op2_Ry, /* * Register operand 2 is extended to full width, while a memory operand