Date: Mon, 9 Jul 2007 11:02:16 +0800 From: zhouyi zhou <zhouzhouyi@FreeBSD.org> To: zhouyi zhou <zhouzhouyi@FreeBSD.org> Cc: freebsd-hackers@FreeBSD.org, freebsd-current@FreeBSD.org Subject: Re: rewrite src/sys/i386/i386/in_cksum.c Message-ID: <20070709110216.459ca250.zhouzhouyi@FreeBSD.org> In-Reply-To: <20070709105547.71827eb8.zhouzhouyi@FreeBSD.org> References: <20070709105547.71827eb8.zhouzhouyi@FreeBSD.org>
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Sorry, previously send the preprocessed version of in_cksum.c:
What really needs to be replaced is for example:
408 if (mlen >= 16) {
409 ADD(0);
410 ADDC(4);
411 ADDC(8);
412 ADDC(12);
413 MOP;
414 w += 8;
415 mlen -= 16;
416 }
On Mon, 9 Jul 2007 10:55:47 +0800
zhouyi zhou <zhouzhouyi@FreeBSD.org> wrote:
> Hey,
> Since FreeBSD update gcc from 3.4.x to 4.2.0, the FreeBSD gdb remote debugger in i386 platform
> will find the TCP/UPD checksum will not be computed right, when calling macro in_cksum
> which calls in_cksum_skip in src/sys/i386/i386/in_cksum.c in case of getting rid of -O flag
> supplied to gcc when compiling(The optimize will interfere with comfortable gdb debugging).
>
> The reason is for example in src/sys/i386/i386/in_cksum.c:
> 126 if (mlen >= 16) {
> 127 __asm volatile ("addl %1, %0" : "+r" (sum) : "g" (((const unsigned int *)w)[0 / 4]));
> 128 __asm volatile ("adcl %1, %0" : "+r" (sum) : "g" (((const unsigned int *)w)[4 / 4]));
> 129 __asm volatile ("adcl %1, %0" : "+r" (sum) : "g" (((const unsigned int *)w)[8 / 4]));
> 130 __asm volatile ("adcl %1, %0" : "+r" (sum) : "g" (((const unsigned int *)w)[12 / 4]));
> 131 __asm volatile ("adcl $0, %0" : "+r" (sum));
> 132 w += 8;
> 133 mlen -= 16;
> 134 }
>
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