I updated a system of us for testing the the compiler and I run into following problem:
cc -c -O -pipe -march=pentium4 -Wall \
-Wredundant-decls -Wnested-externs -Wstrict-prototypes \
-Wmissing-prototypes -Wpointer-arith -Winline \
-Wcast-qual-fformat-extensions -std=c99 -nostdinc \
-I- -I. -I/usr/src/sys -I/usr/src/sys/dev \
-I/usr/src/sys/contrib/dev/acpica \
-I/usr/src/sys/contrib/ipfilter \
-I/usr/src/sys/contrib/dev/ath \
-I/usr/src/sys/contrib/dev/ath/freebsd -D_KERNEL \
-include opt_global.h -fno-common \
-mno-align-long-strings \
-mpreferred-stack-boundary=2 -ffreestanding \
/usr/src/sys/dev/ata/ata-all.c
{standard input}: Assembler messages:
{standard input}:7652: Error: invalid character '_' in mnemonic
*** Error code 1Stop in /usr/obj/usr/src/sys/MOBY. *** Error code 1
Stop in /usr/src. *** Error code 1
Stop in /usr/src.
The lines around the location are:
ata_enclosure_status:
pushl %ebp
movl %esp, %ebp
pushl %edi
pushl %esi
pushl %ebx
subl $24, %esp
movl 8(%ebp), %edi
movl $6, -16(%ebp)
testb $8, 20(%edi)
ds ; je .L2817
movl (%edi), %eax
movl $1, 4(%esp)
movl %eax, (%esp)
call *248(%eax)
movl (%edi), %ecx
movl $0, %eax
movl $128, %edx
#APP
lock ; cmpxchgl %edx,244(%ecx) ;
setz %al ; movzbl %al,%eax ; 1: #
atomic_cmpset_int
#NO_APP
testl %eax, %eax
jne .L2830
movl $0, %esi
movl $128, %ebx
.L2822:The line 7652 is the "#NO_APP". After asking the current@ list I didn't receive any answer so I assumed either noone had the time to look over it or it's not really interesting for any responsible. So I started some research about the '#APP'/'#NO_APP', the code origin, etc.
The '#APP'/'#NO_APP' pair is used by the compiler to mark the assembly section to be reformatted by the as(1) builtin preprocessor. Because that's not the only '#APP'/'#NO_APP' pair, there must be sth. different.
A try to reformat the assembly file produces the experience that the error is gone when the label '1:' is placed on a new line. The question I couldn't answer by myself is now:
is there any difference in the resulting code, if the inline assembly of 'atomic_cmpset_int' will be written like:
static __inline int
atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
{
int res = exp; __asm __volatile (
"" __XSTRING(MPLOCKED) "\n\t"
"cmpxchgl %1,%2\n\t"
"setz %%al\n\t"
"movzbl %%al,%0\n\t"
"1:\n\t"
"# atomic_cmpset_int"
: "+a" (res) /* 0 (result) */
: "r" (src), /* 1 */
"m" (*(dst)) /* 2 */
: "memory"); return (res); }
as it's shown in an example in src/contrib/binutils/gas/config/tc-i386.c?
Or is the resulting code different from the original? I understood the ';' as a instruction sepatator, so for my understanding there will be no difference. But I think about the 'lock' instruction which is required for SMP kernels? How works it here? Does it locks the entire 3 instructions or just the first of them?
It would be great if someone could explain that to me.
Thanks and best regards, Jens
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