fix(asm): ADDQ imm8 frame adjust for 128-255 byte frames

2026-08-28 22:11:24 +02:00
parent 78b12dd427
commit ba4d961b20
1 changed files with 5 additions and 0 deletions
@@ -261,6 +261,11 @@ func subSP(size int) []byte { // SUBQ $size, SP
 	if size >= -128 && size <= 127 {
 		return []byte{0x48, 0x83, 0xEC, byte(int8(size))}
 	}
+	// 128..255 do not fit SUB's unsigned imm8, but the Go assembler
+	// switches to ADDQ $-size, SP whose sign-extended imm8 does.
+	if size >= -255 && size <= 255 {
+		return []byte{0x48, 0x83, 0xC4, byte(int8(-size))}
+	}
 	return append([]byte{0x48, 0x81, 0xEC}, le32(int64(size))...)
 }