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authorJan Kiszka <jan.kiszka@siemens.com>2011-09-29 18:52:11 +0200
committerBlue Swirl <blauwirbel@gmail.com>2011-10-01 06:42:46 +0000
commita4773324b4bc5f15fe9b438e4cfff05e1ab16dfa (patch)
treeca5efb7a06cf3f553b339b7a945447ae242ad6b3
parent7e17a217061e402243499d96fc8dec92162d8b4a (diff)
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tcg-i386: Introduce limited deposit support
x86 cannot provide an optimized generic deposit implementation. But at least for a few special cases, namely for writing bits 0..7, 8..15, and 0..15, versions using only a single instruction are feasible. Introducing such limited support improves emulating 16-bit x86 code on x86, but also rarer cases where 32-bit or 64-bit code accesses bytes or words. Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
-rw-r--r--tcg/i386/tcg-target.c24
-rw-r--r--tcg/i386/tcg-target.h9
-rw-r--r--tcg/tcg-op.h4
-rw-r--r--tcg/tcg.h7
4 files changed, 40 insertions, 4 deletions
diff --git a/tcg/i386/tcg-target.c b/tcg/i386/tcg-target.c
index 281f87d..3069e53 100644
--- a/tcg/i386/tcg-target.c
+++ b/tcg/i386/tcg-target.c
@@ -168,6 +168,10 @@ static int target_parse_constraint(TCGArgConstraint *ct, const char **pct_str)
tcg_regset_set32(ct->u.regs, 0, 0xf);
}
break;
+ case 'Q':
+ ct->ct |= TCG_CT_REG;
+ tcg_regset_set32(ct->u.regs, 0, 0xf);
+ break;
case 'r':
ct->ct |= TCG_CT_REG;
if (TCG_TARGET_REG_BITS == 64) {
@@ -1747,6 +1751,22 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode opc,
break;
#endif
+ OP_32_64(deposit):
+ if (args[3] == 0 && args[4] == 8) {
+ /* load bits 0..7 */
+ tcg_out_modrm(s, OPC_MOVB_EvGv | P_REXB_R | P_REXB_RM,
+ args[2], args[0]);
+ } else if (args[3] == 8 && args[4] == 8) {
+ /* load bits 8..15 */
+ tcg_out_modrm(s, OPC_MOVB_EvGv, args[2], args[0] + 4);
+ } else if (args[3] == 0 && args[4] == 16) {
+ /* load bits 0..15 */
+ tcg_out_modrm(s, OPC_MOVL_EvGv | P_DATA16, args[2], args[0]);
+ } else {
+ tcg_abort();
+ }
+ break;
+
default:
tcg_abort();
}
@@ -1802,6 +1822,8 @@ static const TCGTargetOpDef x86_op_defs[] = {
{ INDEX_op_setcond_i32, { "q", "r", "ri" } },
+ { INDEX_op_deposit_i32, { "Q", "0", "Q" } },
+
#if TCG_TARGET_REG_BITS == 32
{ INDEX_op_mulu2_i32, { "a", "d", "a", "r" } },
{ INDEX_op_add2_i32, { "r", "r", "0", "1", "ri", "ri" } },
@@ -1853,6 +1875,8 @@ static const TCGTargetOpDef x86_op_defs[] = {
{ INDEX_op_ext8u_i64, { "r", "r" } },
{ INDEX_op_ext16u_i64, { "r", "r" } },
{ INDEX_op_ext32u_i64, { "r", "r" } },
+
+ { INDEX_op_deposit_i64, { "Q", "0", "Q" } },
#endif
#if TCG_TARGET_REG_BITS == 64
diff --git a/tcg/i386/tcg-target.h b/tcg/i386/tcg-target.h
index 5088e47..b9c9d4e 100644
--- a/tcg/i386/tcg-target.h
+++ b/tcg/i386/tcg-target.h
@@ -90,7 +90,7 @@ enum {
#define TCG_TARGET_HAS_eqv_i32 0
#define TCG_TARGET_HAS_nand_i32 0
#define TCG_TARGET_HAS_nor_i32 0
-#define TCG_TARGET_HAS_deposit_i32 0
+#define TCG_TARGET_HAS_deposit_i32 1
#if TCG_TARGET_REG_BITS == 64
#define TCG_TARGET_HAS_div2_i64 1
@@ -111,9 +111,14 @@ enum {
#define TCG_TARGET_HAS_eqv_i64 0
#define TCG_TARGET_HAS_nand_i64 0
#define TCG_TARGET_HAS_nor_i64 0
-#define TCG_TARGET_HAS_deposit_i64 0
+#define TCG_TARGET_HAS_deposit_i64 1
#endif
+#define TCG_TARGET_deposit_i32_valid(ofs, len) \
+ (((ofs) == 0 && (len) == 8) || ((ofs) == 8 && (len) == 8) || \
+ ((ofs) == 0 && (len) == 16))
+#define TCG_TARGET_deposit_i64_valid TCG_TARGET_deposit_i32_valid
+
#define TCG_TARGET_HAS_GUEST_BASE
/* Note: must be synced with dyngen-exec.h */
diff --git a/tcg/tcg-op.h b/tcg/tcg-op.h
index 404b637..fea5983 100644
--- a/tcg/tcg-op.h
+++ b/tcg/tcg-op.h
@@ -2045,7 +2045,7 @@ static inline void tcg_gen_deposit_i32(TCGv_i32 ret, TCGv_i32 arg1,
TCGv_i32 arg2, unsigned int ofs,
unsigned int len)
{
- if (TCG_TARGET_HAS_deposit_i32) {
+ if (TCG_TARGET_HAS_deposit_i32 && TCG_TARGET_deposit_i32_valid(ofs, len)) {
tcg_gen_op5ii_i32(INDEX_op_deposit_i32, ret, arg1, arg2, ofs, len);
} else {
uint32_t mask = (1u << len) - 1;
@@ -2064,7 +2064,7 @@ static inline void tcg_gen_deposit_i64(TCGv_i64 ret, TCGv_i64 arg1,
TCGv_i64 arg2, unsigned int ofs,
unsigned int len)
{
- if (TCG_TARGET_HAS_deposit_i64) {
+ if (TCG_TARGET_HAS_deposit_i64 && TCG_TARGET_deposit_i64_valid(ofs, len)) {
tcg_gen_op5ii_i64(INDEX_op_deposit_i64, ret, arg1, arg2, ofs, len);
} else {
uint64_t mask = (1ull << len) - 1;
diff --git a/tcg/tcg.h b/tcg/tcg.h
index 1859fae..de8a1d5 100644
--- a/tcg/tcg.h
+++ b/tcg/tcg.h
@@ -81,6 +81,13 @@ typedef uint64_t TCGRegSet;
#define TCG_TARGET_HAS_deposit_i64 0
#endif
+#ifndef TCG_TARGET_deposit_i32_valid
+#define TCG_TARGET_deposit_i32_valid(ofs, len) 1
+#endif
+#ifndef TCG_TARGET_deposit_i64_valid
+#define TCG_TARGET_deposit_i64_valid(ofs, len) 1
+#endif
+
/* Only one of DIV or DIV2 should be defined. */
#if defined(TCG_TARGET_HAS_div_i32)
#define TCG_TARGET_HAS_div2_i32 0