endbr64 has no operand but comes with a ModR/M byte. Handle it in the
same way as *fence instructions.
Signed-off-by: Yao Zi <zi...@disroot.org>
---
i386-asm.c | 12 +++++++++---
x86_64-asm.h | 3 +++
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/i386-asm.c b/i386-asm.c
index 33783d5f..a3e16fb8 100644
--- a/i386-asm.c
+++ b/i386-asm.c
@@ -1002,15 +1002,21 @@ again:
modrm_index = -1;
modreg_index = -1;
if (pa->instr_type & OPC_MODRM) {
+#ifdef TCC_TARGET_X86_64
if (!nb_ops) {
/* A modrm opcode without operands is a special case (e.g. mfence).
- It has a group and acts as if there's an register operand 0
- (ax). */
+ It has a group and acts as if there's an register operand */
i = 0;
ops[i].type = OP_REG;
- ops[i].reg = 0;
+ if (pa->sym == TOK_ASM_endbr64)
+ ops[i].reg = 2; // dx
+ else if (pa->sym >= TOK_ASM_lfence && pa->sym <= TOK_ASM_sfence)
+ ops[i].reg = 0; // ax
+ else
+ tcc_error("bad MODR/M opcode without operands");
goto modrm_found;
}
+#endif
/* first look for an ea operand */
for(i = 0;i < nb_ops; i++) {
if (op_type[i] & OP_EA)
diff --git a/x86_64-asm.h b/x86_64-asm.h
index e4655a7a..883232ea 100644
--- a/x86_64-asm.h
+++ b/x86_64-asm.h
@@ -538,6 +538,9 @@ ALT(DEF_ASM_OP2(movhps, 0x0f17, 0, OPC_MODRM, OPT_SSE,
OPT_EA | OPT_REG32 ))
DEF_ASM_OP0L(mfence, 0x0fae, 6, OPC_MODRM)
DEF_ASM_OP0L(sfence, 0x0fae, 7, OPC_MODRM)
DEF_ASM_OP1(clflush, 0x0fae, 7, OPC_MODRM, OPT_EA)
+
+ /* Control-Flow Enforcement */
+ DEF_ASM_OP0L(endbr64, 0xf30f1e, 7, OPC_MODRM)
#undef ALT
#undef DEF_ASM_OP0
#undef DEF_ASM_OP0L
--
2.46.0
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