• State Not Answered
  • Locked Locked
  • Replies 3 replies
  • Subscribers 20 subscribers
  • Views 1751 views
  • Users 0 members are here
Options
How was your experience today?
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Keil Named Register Variable not working

Michael Tscharntke

Somebody ever used named register variables successfully and can tell me what i am doing wrong?

example code:

#pragma O0        // optimization off
#pragma thumb     // thumb mode
__global_reg(8) int myR8;
void DAbt_Handler(void) __irq
{
  register unsigned int programCounter __asm ("lr");
  unsigned int          value = programCounter - (unsigned int)0x04;
  register int myR7 __asm("r7");

  myR7 = 0x07;
  myR7++;

  myR8 = 0x08;
  myR8++;

  printf("R2 : %x",programCounter);
  printf("R7: %x",myR7);
  printf("R8 : %x",myR8);
  printf("** Data Abort @%X **\n",value);

  while(1);
}

So in theory myR7 should be translated to Register R7, myR8 (global register definition) should be R8 etc. but if i look into lst file the compiler makes something different of it:

;;;17     void DAbt_Handler(void) __irq
00000c  e2446004          SUB      r6,r4,#4
;;;18     {
;;;19
;;;20       register unsigned int programCounter __asm ("lr");
;;;21       unsigned int          value = programCounter - (unsigned int)0x04;
;;;22       register int myR7 __asm("r7");
;;;23
;;;24       myR7 = 0x07;
000010  e3a05007          MOV      r5,#7
;;;25           myR7++;
000014  e2855001          ADD      r5,r5,#1
;;;26           myR8 = 0x08;
000018  e3a0b008          MOV      r11,#8
;;;27           myR8++;
00001c  e28bb001          ADD      r11,r11,#1
;;;28
;;;29
;;;30           printf("LR : %x",programCounter);
000020  e1a01004          MOV      r1,r4
000024  e28f007c          ADR      r0,|L1.168|
000028  ebfffffe          BL       __2printf
;;;31           printf("R7: %x",myR7);
00002c  e1a01005          MOV      r1,r5
000030  e28f0078          ADR      r0,|L1.176|
000034  ebfffffe          BL       __2printf
;;;32           printf("R8 : %x",myR8);
000038  e1a0100b          MOV      r1,r11
00003c  e28f0074          ADR      r0,|L1.184|
000040  ebfffffe          BL       __2printf

Any hints are welcome.

0