call_apsr.h 997 Bytes
#ifndef CALL_APSR_H
#define CALL_APSR_H

#if __BYTE_ORDER__ != __ORDER_LITTLE_ENDIAN__
#error big endian support not implemented
#endif

union cpsr {
    struct {
        uint32_t filler: 28;
        uint32_t v: 1;
        uint32_t c: 1;
        uint32_t z: 1;
        uint32_t n: 1;
    } flags;
    uint32_t value;
};

__attribute__((noinline, pcs("aapcs"))) static uint32_t call_apsr_f(float a, float b,
                                                                    __attribute__((pcs("aapcs"))) void (*fn)(float, float)) {
  uint32_t result;
  fn(a, b);
  asm volatile("mrs %0, apsr"
               : "=r"(result));
  return result;
}

__attribute__((noinline, pcs("aapcs"))) static uint32_t call_apsr_d(double a, double b,
                                                                    __attribute__((pcs("aapcs"))) void (*fn)(double, double)) {
  uint32_t result;
  fn(a, b);
  asm volatile("mrs %0, apsr"
               : "=r"(result));
  return result;
}

#endif // CALL_APSR_H