C header for SPIM syscalls

spim.h

#ifndef SPIM_H
#define SPIM_H

#include <stddef.h>

__attribute__((always_inline)) static inline void spim_print_int(int value) {
    register unsigned long v0 __asm__("$v0") = 1; 
    register int a0 __asm__("$a0") = value;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "r" (a0)
        : "memory"
    );
}

#ifdef __mips_hard_float

__attribute__((always_inline)) static inline void spim_print_float(float value) {
    register unsigned long v0 __asm__("$v0") = 2; 
    register float f12 __asm__("$f12") = value;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "f" (f12)
        : "memory"
    );
}

__attribute__((always_inline)) static inline void spim_print_double(double value) {
    register unsigned long v0 __asm__("$v0") = 3; 
    register double f12 __asm__("$f12") = value;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "f" (f12)
        : "memory"
    );
}

#else

__attribute__((unused, noinline, error("spim_print_float() requires -mhard-float")))
static void spim_print_float(float) {
    __builtin_unreachable();
}

__attribute__((unused, noinline, error("spim_print_double() requires -mhard-float")))
static void spim_print_double(double) {
    __builtin_unreachable();
}

#endif

__attribute__((always_inline)) static inline void spim_print_string(const char* value) {
    register unsigned long v0 __asm__("$v0") = 4;
    register const char* a0 __asm__("$a0") = value;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "r" (a0)
        : "memory"
    );
}

__attribute__((always_inline)) static inline int spim_read_int(void) {
    register unsigned long v0 __asm__("$v0") = 5;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        :
        : "memory"
    );

    return (int) v0;
}

#ifdef __mips_hard_float

__attribute__((always_inline)) static inline float spim_read_float(void) {
    register unsigned long v0 __asm__("$v0") = 6;
    register float f0 __asm__("$f0");

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0), "=f" (f0)
        :
        : "memory"
    );

    return f0;
}

__attribute__((always_inline)) static inline double spim_read_double(void) {
    register unsigned long v0 __asm__("$v0") = 7;
    register double f0 __asm__("$f0");

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0), "=f" (f0)
        :
        : "memory"
    );

    return f0;
}

#else

__attribute__((unused, noinline, error("spim_read_float() requires -mhard-float")))
static float spim_read_float(void) {
    __builtin_unreachable();
}

__attribute__((unused, noinline, error("spim_read_double() requires -mhard-float")))
static double spim_read_double(void) {
    __builtin_unreachable();
}

#endif

__attribute__((always_inline)) static inline void spim_read_string(char* buffer, size_t length) {
    register unsigned long v0 __asm__("$v0") = 8;
    register char* a0 __asm__("$a0") = buffer;
    register size_t a1 __asm__("$a1") = length;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "r" (a0), "r" (a1)
        : "memory"
    );
}

__attribute__((always_inline)) static inline char* spim_sbrk(size_t size) {
    register unsigned long v0 __asm__("$v0") = 9;
    register size_t a0 __asm__("$a0") = size;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "r" (a0)
        : "memory"
    );

    return (char*) v0;
}

__attribute__((always_inline, noreturn)) static inline void spim_exit(void) {
    register unsigned long v0 __asm__("$v0") = 10;

    __asm__ __volatile__ (
        "syscall"
        :
        : "r" (v0)
        :
    );
    __builtin_unreachable();
}

__attribute__((always_inline)) static inline void spim_print_char(char value) {
    register unsigned long v0 __asm__("$v0") = 11;
    register char a0 __asm__("$a0") = value;

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0)
        : "r" (a0)
        : "memory"
    );
}

__attribute__((always_inline)) static inline char spim_read_char(void) {
    register unsigned long v0 __asm__("$v0") = 12;
    register char a0 __asm__("$a0");

    __asm__ __volatile__ (
        "syscall"
        : "+r" (v0), "=r" (a0)
        :
        : "memory"
    );

    return a0;
}

__attribute__((always_inline, noreturn)) static inline void spim_exit2(int code) {
    register unsigned long v0 __asm__("$v0") = 17;
    register int a0 __asm__("$a0") = code;

    __asm__ __volatile__ (
        "syscall"
        :
        : "r" (v0), "r" (a0)
        :
    );
    __builtin_unreachable();
}

#endif