From a02fe95b33a85f6fc632a9b17abe7f019bdd260b Mon Sep 17 00:00:00 2001
From: Theodore Dubois <tblodt@icloud.com>
Date: Sun, 12 Aug 2018 18:56:26 -0700
Subject: [PATCH] Implement sahf

---
 jit/gadgets-x86/control.S | 19 +++++++++++++------
 jit/gen.c                 |  2 +-
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/jit/gadgets-x86/control.S b/jit/gadgets-x86/control.S
index 577cd9ba..17dc1d5a 100644
--- a/jit/gadgets-x86/control.S
+++ b/jit/gadgets-x86/control.S
@@ -75,14 +75,11 @@
     .else; .ifc \cond,cz
         check_cf
         jnz \target
-        check_res
-        jz \target
+        res_or_flag z, ZF_RES, ZF_FLAG, \target
     .else; .ifc \cond,s
-        check_res
-        js \target
+        res_or_flag s, SF_RES, SF_FLAG, \target
     .else; .ifc \cond,p
-        check_res
-        jp \target
+        res_or_flag p, PF_RES, PF_FLAG, \target
     .else; .ifc \cond,sxo
         check_res
         sets %r14b
@@ -165,3 +162,13 @@
     call helper_expand_flags
     restore_c
     gret
+
+.gadget sahf
+    xchgb %ah, %al
+    movb %al, CPU_eflags(%_cpu)
+    xchgb %al, %ah
+    save_c
+    movq %_cpu, %rdi
+    call helper_expand_flags
+    restore_c
+    gret
diff --git a/jit/gen.c b/jit/gen.c
index 05fd19fd..3263b5b2 100644
--- a/jit/gen.c
+++ b/jit/gen.c
@@ -249,7 +249,7 @@ static inline bool gen_op(struct gen_state *state, gadget_t *gadgets, enum arg a
 
 #define PUSHF() g(pushf)
 #define POPF() g(popf)
-#define SAHF UNDEFINED
+#define SAHF g(sahf)
 #define CLD g(cld)
 #define STD g(std)