Archipelago » qemu

/*

* MIPS o32 Linux syscall example

*

* http://www.linux-mips.org/wiki/RISC/os

* http://www.linux-mips.org/wiki/MIPSABIHistory

* http://www.linux.com/howtos/Assembly-HOWTO/mips.shtml

*

* mipsel-linux-gcc -nostdlib -mno-abicalls -fno-PIC -mabi=32 \

*                  -O2 -static -o hello-mips hello-mips.c

*

*/

#define __NR_SYSCALL_BASE        4000

#define __NR_exit                        (__NR_SYSCALL_BASE+  1)

#define __NR_write                        (__NR_SYSCALL_BASE+  4)

static inline void exit1(int status)

{

    register unsigned long __a0 asm("$4") = (unsigned long) status;

    __asm__ __volatile__ (

        "        .set push        \n"

        "        .set noreorder        \n"

        "        li        $2, %0        \n"

        "        syscall                \n"

        "        .set pop        "

        :

        : "i" (__NR_exit), "r" (__a0)

        : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",

          "memory");

}

static inline int write(int fd, const char *buf, int len)

{

    register unsigned long __a0 asm("$4") = (unsigned long) fd;

    register unsigned long __a1 asm("$5") = (unsigned long) buf;

    register unsigned long __a2 asm("$6") = (unsigned long) len;

    register unsigned long __a3 asm("$7");

    unsigned long __v0;

    __asm__ __volatile__ (

        "        .set push        \n"

        "        .set noreorder        \n"

        "        li        $2, %2        \n"

        "        syscall                \n"

        "        move        %0, $2        \n"

        "        .set pop        "

        : "=r" (__v0), "=r" (__a3)

        : "i" (__NR_write), "r" (__a0), "r" (__a1), "r" (__a2)

        : "$2", "$8", "$9", "$10", "$11", "$12", "$13", "$14", "$15", "$24",

          "memory");

/*    if (__a3 == 0) */

        return (int) __v0;

/*

    errno = __v0;

    return -1;

 */

}

void __start(void)

{

    write (1, "Hello, World!\n", 14);

    exit1 (42);

}