Adjust SETcc instruction encoding on x86-64.

Avoid emitting REX for legacy registers.

diff --git a/src/compiler/x86-64/insts.lisp b/src/compiler/x86-64/insts.lisp
index 442c485..554cb52 100644 (file)
--- a/src/compiler/x86-64/insts.lisp
+++ b/src/compiler/x86-64/insts.lisp
@@ -2752,7 +2752,7 @@
 (define-instruction set (segment dst cond)
   (:printer cond-set ())
   (:emitter
-   (maybe-emit-rex-for-ea segment dst nil)
+   (maybe-emit-rex-for-ea segment dst nil :operand-size :byte)
    (emit-byte segment #b00001111)
    (emit-byte segment (dpb (conditional-opcode cond) (byte 4 0) #b10010000))
    (emit-ea segment dst #b000)))