How to link assembly file(.s file) to a C program

Question

The file assem.s contains a function in assembly code. test.c calls the function, but I'm getting the following errors:

mips-mti-elf-gcc -o test test.c assem.s
In file included from test.c:2:0:
assem.s:1:2: error: expected identifier or '(' before '.' token
  .text
  ^
assem.s:3:22: error: stray '@' in program
  .type asm_memcheck, @function
                      ^

assem.s: Assemble messages:
assem.s:6: Warning: used $at without ".set noat"
assem.s:38:  Warning: .end directive without a preceding .ent directive

My source files are as follows: test.c note that local variables a,b,c and d has no significance in the program. It's mainly used to observe the values in the registers.

  1 #include<stdio.h>
  2 #include"assem.s"
  3
  4 extern void asm_memcheck();
  5
  6 int main()
  7 {
  8 int a=1;
  9 int b=2;
 10 int c=3;
 11 float d=4.0;
 12
 13 asm_memcheck();
 14
 15 }
 16

assem.s:

  1         .text
  2         .globl asm_memcheck
  3         .type   asm_memcheck, @function
  4 asm_memcheck:
  5         sw $zero,0xFFF00000
  6         sw $at,0xFFF00004
  7         sw $v0,0xFFF00008
  8         sw $v1,0xFFF0000C
  9         sw $a0,0xFFF00010
 10         sw $a1,0xFFF00014
 11         sw $a2,0xFFF00018
 12         sw $a3,0xFFF0001C
 13         sw $t0,0xFFF00020
 14         sw $t1,0xFFF00024
 15         sw $t2,0xFFF00028
 16         sw $t3,0xFFF0002C
 17         sw $t4,0xFFF00030
 18         sw $t5,0xFFF00034
 19         sw $t6,0xFFF00038
 20         sw $t7,0xFFF0003C
 21         sw $s0,0xFFF00040
 22         sw $s1,0xFFF00044
 23         sw $s2,0xFFF00048
 24         sw $s3,0xFFF0004C
 25         sw $s4,0xFFF00050
 26         sw $s5,0xFFF00054
 27         sw $s6,0xFFF00058
 28         sw $s7,0xFFF0005C
 29         sw $t8,0xFFF00060
 30         sw $t9,0xFFF00064
 31         sw $k0,0xFFF00068
 32         sw $k1,0xFFF0006C
 33         sw $gp,0xFFF00070
 34         sw $sp,0xFFF00074
 35         sw $fp,0xFFF00078
 36         sw $ra,0xFFF0007C
 37
 38         .end asm_memcheck
 39

Answer 1

The problem you see comes from the line #include"assem.s": the C compiler try to read assembly code as it was C code.

So, do not include "assem.s" in your c code:

test.c

#include<stdio.h>
extern void asm_memcheck();

int main()
{
    int a=1;
    int b=2;
    int c=3;
    float d=4.0;
    asm_memcheck();
}

And build as you wrote before:

mips-mti-elf-gcc -o test test.c assem.s

Answer 2

If you just want to include it as a quick hack, you could inline it.

#include <stdio.h>

int main()
{
    int a=1;
    int b=2;
    int c=3;
    float d=4.0;

    asm("sw $zero,0xFFF00000\n\t"
        "sw $at,0xFFF00004\n\t"
        "sw $v0,0xFFF00008\n\t"
        "sw $v1,0xFFF0000C\n\t"
        "sw $a0,0xFFF00010\n\t"
        "sw $a1,0xFFF00014\n\t"
        "sw $a2,0xFFF00018\n\t"
        "sw $a3,0xFFF0001C\n\t"
        "sw $t0,0xFFF00020\n\t"
        "sw $t1,0xFFF00024\n\t"
        "sw $t2,0xFFF00028\n\t"
        "sw $t3,0xFFF0002C\n\t"
        "sw $t4,0xFFF00030\n\t"
        "sw $t5,0xFFF00034\n\t"
        "sw $t6,0xFFF00038\n\t"
        "sw $t7,0xFFF0003C\n\t"
        "sw $s0,0xFFF00040\n\t"
        "sw $s1,0xFFF00044\n\t"
        "sw $s2,0xFFF00048\n\t"
        "sw $s3,0xFFF0004C\n\t"
        "sw $s4,0xFFF00050\n\t"
        "sw $s5,0xFFF00054\n\t"
        "sw $s6,0xFFF00058\n\t"
        "sw $s7,0xFFF0005C\n\t"
        "sw $t8,0xFFF00060\n\t"
        "sw $t9,0xFFF00064\n\t"
        "sw $k0,0xFFF00068\n\t"
        "sw $k1,0xFFF0006C\n\t"
        "sw $gp,0xFFF00070\n\t"
        "sw $sp,0xFFF00074\n\t"
        "sw $fp,0xFFF00078\n\t"
        "sw $ra,0xFFF0007C");
}

If you want it to be a separate file, I think you would need to use an assembler and then link the result in somehow.