From 770ad4b1a93892619759d3779a8fcb973ca26bb9 Mon Sep 17 00:00:00 2001
From: maartenbrock <maartenbrock@4a8a32a2-be11-0410-ad9d-d568d2c75423>
Date: Thu, 22 Sep 2005 16:43:33 +0000
Subject: [PATCH] * src/mcs51/gen.c (genMinus): fix for undetected bug
 introduced 3 months   ago by me * support/regression/tests/addsub.c: added
 test for the bug

git-svn-id: https://sdcc.svn.sourceforge.net/svnroot/sdcc/trunk/sdcc@3896 4a8a32a2-be11-0410-ad9d-d568d2c75423
---
 ChangeLog                         |  6 +++++
 src/mcs51/gen.c                   | 41 ++++++++++++++++++++-----------
 support/regression/tests/addsub.c |  3 +++
 3 files changed, 36 insertions(+), 14 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 2885d07d..9dbe8a17 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2005-09-22 Maarten Brock <sourceforge.brock AT dse.nl>
+
+	* src/mcs51/gen.c (genMinus): fix for undetected bug introduced 3 months
+	  ago by me
+	* support/regression/tests/addsub.c: added test for the bug
+
 2005-09-21 Raphael Neider <rneider AT web.de>
 
 	* device/include/pic16/pic18f1220.h,
diff --git a/src/mcs51/gen.c b/src/mcs51/gen.c
index 7ae3fa4e..317a4b16 100644
--- a/src/mcs51/gen.c
+++ b/src/mcs51/gen.c
@@ -4314,7 +4314,7 @@ release:
 }
 
 /*-----------------------------------------------------------------*/
-/* genMinusDec :- does subtraction with deccrement if possible     */
+/* genMinusDec :- does subtraction with decrement if possible      */
 /*-----------------------------------------------------------------*/
 static bool
 genMinusDec (iCode * ic)
@@ -4527,22 +4527,35 @@ genMinus (iCode * ic)
 
       while (size--)
         {
-          if (useCarry || ((lit >> (offset * 8)) & 0x0FFL)) {
+          if (useCarry || ((lit >> (offset * 8)) & 0x0FFL))
+            {
             MOVA (aopGet (IC_LEFT (ic), offset, FALSE, FALSE));
-            if (!offset && !size && lit== (unsigned long) -1) {
-              emitcode ("dec", "a");
-            } else if (!useCarry) {
-              /* first add without previous c */
-              emitcode ("add", "a,#0x%02x",
-                        (unsigned int) ((lit >> (offset * 8)) & 0x0FFL));
-              useCarry = TRUE;
-            } else {
-              emitcode ("addc", "a,#0x%02x",
-                        (unsigned int) ((lit >> (offset * 8)) & 0x0FFL));
+              if (!offset && !size && lit== (unsigned long) -1)
+                {
+                  emitcode ("dec", "a");
+                }
+              else if (!useCarry)
+                {
+                  /* first add without previous c */
+                  emitcode ("add", "a,#0x%02x",
+                            (unsigned int) ((lit >> (offset * 8)) & 0x0FFL));
+                  useCarry = TRUE;
+                }
+              else
+                {
+                  emitcode ("addc", "a,#0x%02x",
+                            (unsigned int) ((lit >> (offset * 8)) & 0x0FFL));
+                }
+              aopPut (IC_RESULT (ic), "a", offset++, isOperandVolatile (IC_RESULT (ic), FALSE));
             }
-            aopPut (IC_RESULT (ic), "a", offset++, isOperandVolatile (IC_RESULT (ic), FALSE));
-            } else {
+          else
+            {
               /* no need to add zeroes */
+              if (!sameRegs (AOP (IC_RESULT (ic)), AOP (IC_LEFT (ic))))
+                {
+                  aopPut (IC_RESULT (ic), aopGet (IC_LEFT (ic), offset, FALSE, FALSE),
+                          offset, isOperandVolatile (IC_RESULT (ic), FALSE));
+                }
               offset++;
             }
         }
diff --git a/support/regression/tests/addsub.c b/support/regression/tests/addsub.c
index 641f7098..3fb3dc1a 100644
--- a/support/regression/tests/addsub.c
+++ b/support/regression/tests/addsub.c
@@ -67,4 +67,7 @@ testSub(void)
   
   result = left-right;
   ASSERT(result == (-39+20));
+
+  result = left-(signed)0x1200;
+  ASSERT(result == ({type})(-39-(signed)0x1200));
 }
-- 
2.47.2