From: j8takagi <j8takagi@nifty.com>
Date: Mon, 1 Feb 2010 23:53:38 +0000 (+0900)
Subject: ADDL、SUBL命令の内部構造を変更
X-Git-Tag: v0.1~74^2
X-Git-Url: http://j8takagi.net/cgi-bin/gitweb.cgi?p=YACASL2.git;a=commitdiff_plain;h=fdbed778ff1f7c889e76e11538b51cbecd967e94

ADDL、SUBL命令の内部構造を変更
---

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 */