diff options
| -rw-r--r-- | tcg/i386/tcg-target.c | 91 |
1 files changed, 60 insertions, 31 deletions
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c index 5d5e5e4..56800ff 100644 --- a/tcg/i386/tcg-target.c +++ b/tcg/i386/tcg-target.c @@ -174,6 +174,7 @@ static inline int tcg_target_const_match(tcg_target_long val, #define OPC_JCC_short (0x70) /* ... plus condition code */ #define OPC_JMP_long (0xe9) #define OPC_JMP_short (0xeb) +#define OPC_LEA (0x8d) #define OPC_MOVB_EvGv (0x88) /* stores, more or less */ #define OPC_MOVL_EvGv (0x89) /* stores, more or less */ #define OPC_MOVL_GvEv (0x8b) /* loads, more or less */ @@ -272,40 +273,70 @@ static inline void tcg_out_modrm(TCGContext *s, int opc, int r, int rm) tcg_out8(s, 0xc0 | (r << 3) | rm); } -/* rm == -1 means no register index */ -static inline void tcg_out_modrm_offset(TCGContext *s, int opc, int r, int rm, - int32_t offset) +/* Output an opcode with a full "rm + (index<<shift) + offset" address mode. + We handle either RM and INDEX missing with a -1 value. */ + +static void tcg_out_modrm_sib_offset(TCGContext *s, int opc, int r, int rm, + int index, int shift, int32_t offset) { + int mod, len; + + if (index == -1 && rm == -1) { + /* Absolute address. */ + tcg_out_opc(s, opc); + tcg_out8(s, (r << 3) | 5); + tcg_out32(s, offset); + return; + } + tcg_out_opc(s, opc); + + /* Find the length of the immediate addend. Note that the encoding + that would be used for (%ebp) indicates absolute addressing. */ if (rm == -1) { - tcg_out8(s, 0x05 | (r << 3)); - tcg_out32(s, offset); + mod = 0, len = 4, rm = 5; } else if (offset == 0 && rm != TCG_REG_EBP) { - if (rm == TCG_REG_ESP) { - tcg_out8(s, 0x04 | (r << 3)); - tcg_out8(s, 0x24); - } else { - tcg_out8(s, 0x00 | (r << 3) | rm); - } - } else if ((int8_t)offset == offset) { - if (rm == TCG_REG_ESP) { - tcg_out8(s, 0x44 | (r << 3)); - tcg_out8(s, 0x24); - } else { - tcg_out8(s, 0x40 | (r << 3) | rm); - } - tcg_out8(s, offset); + mod = 0, len = 0; + } else if (offset == (int8_t)offset) { + mod = 0x40, len = 1; } else { - if (rm == TCG_REG_ESP) { - tcg_out8(s, 0x84 | (r << 3)); - tcg_out8(s, 0x24); + mod = 0x80, len = 4; + } + + /* Use a single byte MODRM format if possible. Note that the encoding + that would be used for %esp is the escape to the two byte form. */ + if (index == -1 && rm != TCG_REG_ESP) { + /* Single byte MODRM format. */ + tcg_out8(s, mod | (r << 3) | rm); + } else { + /* Two byte MODRM+SIB format. */ + + /* Note that the encoding that would place %esp into the index + field indicates no index register. */ + if (index == -1) { + index = 4; } else { - tcg_out8(s, 0x80 | (r << 3) | rm); + assert(index != TCG_REG_ESP); } + + tcg_out8(s, mod | (r << 3) | 4); + tcg_out8(s, (shift << 6) | (index << 3) | rm); + } + + if (len == 1) { + tcg_out8(s, offset); + } else if (len == 4) { tcg_out32(s, offset); } } +/* rm == -1 means no register index */ +static inline void tcg_out_modrm_offset(TCGContext *s, int opc, int r, int rm, + int32_t offset) +{ + tcg_out_modrm_sib_offset(s, opc, r, rm, -1, 0, offset); +} + /* Generate dest op= src. Uses the same ARITH_* codes as tgen_arithi. */ static inline void tgen_arithr(TCGContext *s, int subop, int dest, int src) { @@ -710,10 +741,9 @@ static void tcg_out_qemu_ld(TCGContext *s, const TCGArg *args, tgen_arithi(s, ARITH_AND, r0, TARGET_PAGE_MASK | ((1 << s_bits) - 1), 0); tgen_arithi(s, ARITH_AND, r1, (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0); - tcg_out_opc(s, 0x8d); /* lea offset(r1, %ebp), r1 */ - tcg_out8(s, 0x80 | (r1 << 3) | 0x04); - tcg_out8(s, (5 << 3) | r1); - tcg_out32(s, offsetof(CPUState, tlb_table[mem_index][0].addr_read)); + tcg_out_modrm_sib_offset(s, OPC_LEA, r1, TCG_AREG0, r1, 0, + offsetof(CPUState, + tlb_table[mem_index][0].addr_read)); /* cmp 0(r1), r0 */ tcg_out_modrm_offset(s, OPC_CMP_GvEv, r0, r1, 0); @@ -903,10 +933,9 @@ static void tcg_out_qemu_st(TCGContext *s, const TCGArg *args, tgen_arithi(s, ARITH_AND, r0, TARGET_PAGE_MASK | ((1 << s_bits) - 1), 0); tgen_arithi(s, ARITH_AND, r1, (CPU_TLB_SIZE - 1) << CPU_TLB_ENTRY_BITS, 0); - tcg_out_opc(s, 0x8d); /* lea offset(r1, %ebp), r1 */ - tcg_out8(s, 0x80 | (r1 << 3) | 0x04); - tcg_out8(s, (5 << 3) | r1); - tcg_out32(s, offsetof(CPUState, tlb_table[mem_index][0].addr_write)); + tcg_out_modrm_sib_offset(s, OPC_LEA, r1, TCG_AREG0, r1, 0, + offsetof(CPUState, + tlb_table[mem_index][0].addr_write)); /* cmp 0(r1), r0 */ tcg_out_modrm_offset(s, OPC_CMP_GvEv, r0, r1, 0); |