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[applied patch] add overflow checking comments to mips.igen


originally from:

http://sources.redhat.com/ml/gdb-patches/2000-12/msg00117.html

split out and recycled for your pleasure.  8-)


These aren't just no-op comments; they tell people that overflow
checking really is being done, and where.  (And, obviously, somebody
thought it appropriate to put this in in ... one of the 6 places,
previous.  "hmm.")


cgd
===================================================================
2002-02-11  Chris Demetriou  <cgd@broadcom.com>

	* mips.igen (ADD, ADDI, DADDI, DSUB, SUB): Add comment
	indicating that ALU32_END or ALU64_END are there to check
	for overflow.
	(DADD): Likewise, but also remove previous comment about
	overflow checking.

Index: mips.igen
===================================================================
RCS file: /cvs/src/src/sim/mips/mips.igen,v
retrieving revision 1.9
diff -u -r1.9 mips.igen
--- mips.igen	2002/02/11 06:13:49	1.9
+++ mips.igen	2002/02/11 22:45:39
@@ -237,7 +237,7 @@
   {
     ALU32_BEGIN (GPR[RS]);
     ALU32_ADD (GPR[RT]);
-    ALU32_END (GPR[RD]);
+    ALU32_END (GPR[RD]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RD]);
 }
@@ -255,7 +255,7 @@
   {
     ALU32_BEGIN (GPR[RS]);
     ALU32_ADD (EXTEND16 (IMMEDIATE));
-    ALU32_END (GPR[RT]);
+    ALU32_END (GPR[RT]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RT]);
 }
@@ -709,12 +709,11 @@
 *vr4100:
 *vr5000:
 {
-  /* this check's for overflow */
   TRACE_ALU_INPUT2 (GPR[RS], GPR[RT]);
   {
     ALU64_BEGIN (GPR[RS]);
     ALU64_ADD (GPR[RT]);
-    ALU64_END (GPR[RD]);
+    ALU64_END (GPR[RD]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RD]);
 }
@@ -732,7 +731,7 @@
   {
     ALU64_BEGIN (GPR[RS]);
     ALU64_ADD (EXTEND16 (IMMEDIATE));
-    ALU64_END (GPR[RT]);
+    ALU64_END (GPR[RT]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RT]);
 }
@@ -1181,7 +1180,7 @@
   {
     ALU64_BEGIN (GPR[RS]);
     ALU64_SUB (GPR[RT]);
-    ALU64_END (GPR[RD]);
+    ALU64_END (GPR[RD]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RD]);
 }
@@ -2210,7 +2209,7 @@
   {
     ALU32_BEGIN (GPR[RS]);
     ALU32_SUB (GPR[RT]);
-    ALU32_END (GPR[RD]);
+    ALU32_END (GPR[RD]);   /* This checks for overflow.  */
   }
   TRACE_ALU_RESULT (GPR[RD]);
 }


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