| /* |
| * Generic syscall call. |
| * Upon entry: |
| * %eax: system call number - caller save |
| * %ebx: arg0 to system call - callee save |
| * %ecx: arg1 - caller save |
| * %edx: arg2 - caller save |
| * %esi: arg3 - callee save |
| * %edi: arg4 - callee save |
| * %ebp: arg5 - callee save |
| */ |
| |
| #include <sys/linux-syscalls.h> |
| |
| .text |
| .type syscall, @function |
| .globl syscall |
| .align 4 |
| |
| syscall: |
| # Push the callee save registers. |
| push %ebx |
| push %esi |
| push %edi |
| push %ebp |
| |
| # Load all the arguments from the calling frame. |
| # (Not all will be valid, depending on the syscall.) |
| mov 20(%esp),%eax |
| mov 24(%esp),%ebx |
| mov 28(%esp),%ecx |
| mov 32(%esp),%edx |
| mov 36(%esp),%esi |
| mov 40(%esp),%edi |
| mov 44(%esp),%ebp |
| |
| # Make the system call. |
| int $0x80 |
| |
| # Error? |
| cmpl $-4095, %eax |
| jb 1f |
| # Yes, so set errno. |
| negl %eax |
| pushl %eax |
| call __set_errno |
| addl $4, %esp |
| orl $-1, %eax |
| 1: |
| # Restore the callee save registers. |
| pop %ebp |
| pop %edi |
| pop %esi |
| pop %ebx |
| ret |
