Re: [Patch] / 0 should send SIGFPE not SIGTRAP...

[David Daney <ddaney@avtrex.com>]

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It might help if I attached the patch.  Here it is...

David Daney wrote:

> I am getting a SIGTRAP whenever an integer divide by 0 happens.  It 
> should be sending SIGFPE.
>
> It looks like kernel/traps.c is a little messed up.
>
> The attached patch fixes it for me.
>
> The decoding of the break instruction was selecting the wrong bits.  
> It looks like the trap instruction decoding was messed up also.  The 
> patch fixes trap also, but I could not figure out how to get gcc to 
> generate the trap form of division, so that part is untested.
>
> David Daney.
>


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--- ../linux-avtrex/linux/arch/mips/kernel/traps.c	2004-02-26 11:14:09.000000000 -0800
+++ arch/mips/kernel/traps.c	2004-06-11 10:13:59.000000000 -0700
@@ -598,7 +598,7 @@
 	 * code starts left to bit 16 instead to bit 6 in the opcode.
 	 * Gas is bug-compatible ...
 	 */
-	bcode = ((opcode >> 16) & ((1 << 20) - 1));
+	bcode = ((opcode >> 6) & ((1 << 20) - 1));
 
 	/*
 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all break
@@ -633,7 +633,7 @@
 
 	/* Immediate versions don't provide a code.  */
 	if (!(opcode & OPCODE))
-		tcode = ((opcode >> 6) & ((1 << 20) - 1));
+		tcode = ((opcode >> 6) & ((1 << 10) - 1));
 
 	/*
 	 * (A short test says that IRIX 5.3 sends SIGTRAP for all trap