error: unknown register name '%eax' in 'asm'

roMoon · 03-15-2011, 05:27 AM

An error occur when I compile my inline assemble code with a alpha/linux cross compiler.

code:

Code:

#define CPU_ID(cpu_iid)                   \
       __asm__ __volatile__ (             \
       "mov $0, %%eax\n\t"                \
       "mov %%eax, %0\n\t"                \
       :"=m"(cpu_iid)                     \
       :                                  \
       :"%eax"                            \
       );

error:

Quote:

error: unknown register name '%eax' in 'asm'

does anyone know how to solve this problem? thanks for help.

business_kid · 03-15-2011, 10:21 AM

the %.

eax is a register, I think. (Did very little x86 asm). %eax is not a register.

paulsm4 · 03-15-2011, 12:18 PM

Quote:

%eax is not a register

More specifically, "%eax" is not an ALPHA register - it's an x86 register.

In "as" assembler syntax (vs. "masm" assembler syntax).

This link might help:
http://www.alphalinux.org/wiki/index.php/Alpha_Assembly

PS:
The snippet in question is a macro that reads the CPU ID from an Intel/AMD x86 processor. As a workaround, perhaps you might just hard-code some dummy CPU ID for your Alpha port?