[PATCH] 2.2.19pre hfmodem/refclock.c asm statement error

From: Jari Ruusu (jari.ruusu@pp.inet.fi)
Date: Fri Mar 09 2001 - 12:54:23 EST


drivers/char/hfmodem/refclock.c fails to compile with "gcc version 2.95.2
20000220 (Debian GNU/Linux)", but compiles normally with "gcc version
2.7.2.3". GNU assembler 2.9.5 was used in both cases. Here is the error
message:

refclock.c: In function `hfmodem_refclock_current':
refclock.c:136: Invalid `asm' statement:
refclock.c:136: fixed or forbidden register 0 (ax) was spilled for class AREG.

Here is the offending line:
__asm__("mull %2" : "=d" (tmp2), "=a" (tmp4) : "m" (scale_rdtsc), "1" (tmp0) : "ax");

It appears that above code declares register eax as output and globbered
register simultaneously. My gcc docs say: "You may not write a clobber
description in a way that overlaps with an input or output operand." Below
is a patch against 2.2.19pre16 to fix this. Please consider applying.

Regards,
Jari Ruusu <jari.ruusu@pp.inet.fi>

--- linux-2.2.19pre16/drivers/char/hfmodem/refclock.c Tue Jan 4 20:12:14 2000
+++ linux/drivers/char/hfmodem/refclock.c Fri Mar 9 17:59:31 2001
@@ -133,7 +133,7 @@
                         "subl %2,%%eax\n\t"
                         "sbbl %3,%%edx\n\t" : "=&a" (tmp0), "=&d" (tmp1)
                         : "m" (dev->clk.starttime_lo), "m" (dev->clk.starttime_hi));
- __asm__("mull %2" : "=d" (tmp2), "=a" (tmp4) : "m" (scale_rdtsc), "1" (tmp0) : "ax");
+ __asm__("mull %2" : "=d" (tmp2), "=a" (tmp4) : "m" (scale_rdtsc), "1" (tmp0));
                 __asm__("mull %1" : "=a" (tmp3) : "m" (scale_rdtsc), "a" (tmp1) : "dx");
                 curtime = tmp2 + tmp3;
                 goto time_known;
-
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This archive was generated by hypermail 2b29 : Thu Mar 15 2001 - 21:00:10 EST