inline.c

Keil公司提供的ARM7中有关内联函数的应用实例

/******************************************************************************/
/* INLINE.C: In-line Assembly Demo                                            */
/******************************************************************************/
/* This file is part of the uVision/ARM development tools.                    */
/* Copyright (c) 2005-2006 Keil Software. All rights reserved.                */
/* This software may only be used under the terms of a valid, current,        */
/* end user licence from KEIL for a compatible version of KEIL software       */
/* development tools. Nothing else gives you the right to use this software.  */
/******************************************************************************/

#include <stdio.h>                /* prototype declarations for I/O functions */

extern void init_serial (void);


/*
 * User 'strcpy' Function in In-line Assembly
 */

void my_strcpy (char *dst, const char *src) {
  int ch;

  __asm {
  loop: LDRB    ch, [src], #1
        STRB    ch, [dst], #1
        CMP     ch, #0
        BNE     loop
  }
}


/*
 * Multiply & Accumulate in In-line Assembly
 */

#define lo64(a) (((unsigned int *)&a)[0])  // Low  32-bits of a long long
#define hi64(a) (((         int *)&a)[1])  // High 32-bits of a long long

__inline __int64 mlal (__int64 sum, int a, int b) {
  __asm { SMLAL lo64(sum), hi64(sum), a, b }
  return sum;
}


const char *txt = "Hello World!";
      char buf[16];

int a[10] = {  1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };
int b[10] = { 10, 9, 8, 7, 6, 5, 4, 3, 2, 1  };

__int64 sum;



int main (void) {
  int n;

  init_serial();

  my_strcpy(buf, txt);             // Copy String
  printf("%s\n\n", buf);

  sum = 0;
  printf("Dotproduct = ");
  for (n = 0; n < 10; n++) {
    sum = mlal(sum, a[n], b[n]);   // Multiply & Accumulate
    if (n != 0) putchar('+');
    printf("%d*%d", a[n], b[n]);
  }
  printf(" = %lld\n", sum);

  while (1) {                          /* An embedded program does not stop and       */
    ;  /* ... */                       /* never returns. We use an endless loop.      */
  }                                    /* Replace the dots (...) with your own code.  */

}