Re: [avr-gcc-list] inline assembler problem

[Bruce D. Lightner]

Matte,

> Since some of you wanted to view the whole testprogram in order to help
> me track the error I've struggeling with, I post it here. The compiler
> I'm using is still the avr-gcc-3.3.1. 
> The functions in the code below I did implement in order to have some
> simple functions to learn from. 
>
> #include <inttypes.h>
>
> #define PORT_A 0x1B
> #define DDR_A 0x1A
> #define PIN_A 0x19
>
> uint8_t read(const uint8_t adr) {
>   uint8_t p;
>   asm volatile ("in %0, %1" : "=r" (p) : "I" (adr));
>   return p;
> }
>
> uint8_t fastSBI(const uint8_t port, const uint8_t bit) {
>   asm volatile("sbi %0, %1" : : "I" (port), "I" (bit));
> }
>
> int main(void) {
>   uint8_t port_a = PORT_A;
>   uint8_t ddr_a = DDR_A;
>   uint8_t pin = 3;
>   uint8_t data;
>  
>   data = read(port_a);
>   fastSBI(ddr_a, pin);
>   
>   return 0;
> }

This works...

#include <inttypes.h>

#define PORT_A 0x1B
#define DDR_A 0x1A
#define PIN_A 0x19

#define read(adr) ({ \
  uint8_t p; \
  asm volatile ("in %0, %1" \
      : "=r" (p) : "I" ((uint8_t)(adr))); \
  p; \
})

#define fastSBI(port, bit) ({ \
  asm volatile("sbi %0, %1" \
      : : "I" ((uint8_t)(port)), "I" ((uint8_t)(bit))); \
})

int main(void) {
  uint8_t data;

  data = read(PORT_A);
  fastSBI(DDR_A, 3);
  return 0;
}

Best regards,

Bruce

--
 Bruce D. Lightner
 Lightner Engineering
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