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  1. #include <stdio.h>
  2. #include <stdbool.h>
  3. #include <stdint.h>
  4.  
  5. static uint32_t data = 0xEDEDF0F0;
  6.  
  7. static void asic_spi_read_tx(uint32_t address, uint32_t * const read_data)
  8. {
  9. 	*read_data = data;
  10. }
  11.  
  12. static void asic_spi_write_tx(uint32_t address, uint32_t new_data, bool read_now)
  13. {
  14. 	data = new_data;
  15. 	data |= 16;
  16. }
  17.  
  18. static bool read_modify_bits(uint32_t modify_mask, uint32_t new_bits)
  19. {
  20. 	bool success = true;
  21. 	uint32_t address = 0;
  22.     uint32_t read_data = 0;
  23.     asic_spi_read_tx(address, &read_data);
  24.     printf("initial read_data = %x\n", read_data);
  25.     uint32_t new_data = read_data;
  26.     // Modify only masked bits
  27.     for (uint32_t bit = 0; bit < 32; bit++)
  28.     {
  29.         if ((modify_mask & (1 << bit)) != 0)
  30.         {
  31.             // Bit is masked
  32.             if ((new_bits & (1 << bit)) != 0)
  33.             {
  34.                 // Bit should be set
  35.                 new_data |= 1 << bit;
  36.                 printf("Setting bit %u\n", bit);
  37.             }
  38.             else
  39.             {
  40.                 // Bit should be cleared
  41.                 new_data &= ~(1 << bit);
  42.                 printf("Clearing bit %u\n", bit);
  43.             }
  44.         }
  45.     }
  46.     // Write new bits
  47.     asic_spi_write_tx(address, new_data, true);
  48.     // Read to verify bits were properly set/cleared
  49.     asic_spi_read_tx(address, &read_data);
  50.     // Verify bits were set
  51.     if ((read_data & modify_mask) != new_bits)
  52.     {
  53.     	printf("read_data = %x\n", read_data);
  54.         success = false;
  55.     }
  56.     else
  57.     {
  58.     	printf("read_data = %x\n", read_data);
  59.     }
  60.     return success;
  61. }
  62.  
  63. int main(void) {
  64. 	// your code goes here
  65. 	const bool success = read_modify_bits(0xFFFF, 0x0F0F);
  66. 	if (success)
  67. 	{
  68. 		printf("SUCCESS!");
  69. 	}
  70. 	else
  71. 	{
  72. 		printf("FAILURE!");
  73. 	}
  74.  
  75. 	return 0;
  76. }
  77.  
Success #stdin #stdout 0.01s 5320KB
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stdin
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Standard input is empty
stdout
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initial read_data = ededf0f0
Setting bit 0
Setting bit 1
Setting bit 2
Setting bit 3
Clearing bit 4
Clearing bit 5
Clearing bit 6
Clearing bit 7
Setting bit 8
Setting bit 9
Setting bit 10
Setting bit 11
Clearing bit 12
Clearing bit 13
Clearing bit 14
Clearing bit 15
read_data = eded0f1f
FAILURE!
https://ideone.com/tkPxI8
language:
C (gcc 8.3)
created:
14 days ago
visibility:
public

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