From fdbed778ff1f7c889e76e11538b51cbecd967e94 Mon Sep 17 00:00:00 2001
From: j8takagi <j8takagi@nifty.com>
Date: Tue, 2 Feb 2010 08:53:38 +0900
Subject: [PATCH] =?utf8?q?ADDL=E3=80=81SUBL=E5=91=BD=E4=BB=A4=E3=81=AE?=
 =?utf8?q?=E5=86=85=E9=83=A8=E6=A7=8B=E9=80=A0=E3=82=92=E5=A4=89=E6=9B=B4?=
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---
 src/exec.c | 18 ++----------------
 1 file changed, 2 insertions(+), 16 deletions(-)

diff --git a/src/exec.c b/src/exec.c
index 4b3ed78..1862973 100644
--- a/src/exec.c
+++ b/src/exec.c
@@ -99,7 +99,7 @@ WORD addl(WORD val0, WORD val1)
     FR = 0x0;
 
     temp = val0 + val1;
-    if(temp > 65535) {
+    if(temp < 0 || temp > 65535) {
         FR += OF;
     }
     res = (WORD)(temp & 0xFFFF);
@@ -114,21 +114,7 @@ WORD addl(WORD val0, WORD val1)
 /* 論理減算。フラグを設定して値を返す */
 WORD subl(WORD val0, WORD val1)
 {
-    long temp;
-    WORD res;
-    FR = 0x0;
-
-    temp = val0 - val1;
-    if(temp < 0) {
-        FR += OF;
-    }
-    res = (WORD)(temp & 0xFFFF);
-    if((res & 0x8000) > 0) {
-        FR += SF;
-    } else if(res == 0) {
-        FR += ZF;
-    }
-    return res;
+    return addl(val0, (~val1 + 1));
 }
 
 /* 算術比較のフラグ設定。OFは常に0 */
-- 
2.18.0