Created
August 2, 2021 05:17
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Add RGB565 colors together with "software packed" method
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| #include <stdint.h> | |
| uint16_t addRGB565( uint16_t color1, uint16_t color2 ) { | |
| uint16_t c; | |
| c = ( ( color1 & color2 ) + ( ( ( color1 ^ color2 ) & 0xf7de ) >> 1)) & 0x8410; | |
| c = ( ( ( ( ( c + 0xfbdf0 ) ) >> 5 ) & 0xfbff ) + 0x200 ) ^ 0x7bef; | |
| return (color1 + color2 - c) | c; | |
| } | |
| // testbench | |
| #include <stdio.h> | |
| #define R_bits 5 | |
| #define G_bits 6 | |
| #define B_bits 5 | |
| #define MIN(a, b) ((a) < (b) ? (a) : (b)) | |
| int main(void) { | |
| for ( uint16_t r1 = 0 ; r1 < ( 1 << R_bits ) ; r1 ++ ) { | |
| printf( "%d\n", r1 ); | |
| for ( uint16_t g1 = 0 ; g1 < ( 1 << G_bits ) ; g1 ++ ) { | |
| for ( uint16_t b1 = 0 ; b1 < ( 1 << B_bits ) ; b1 ++ ) { | |
| uint16_t color1 = ( r1 << ( G_bits + B_bits ) ) | ( g1 << B_bits ) | b1; | |
| for ( uint16_t r2 = 0 ; r2 < ( 1 << R_bits ) ; r2 ++ ) { | |
| for ( uint16_t g2 = 0 ; g2 < ( 1 << G_bits ) ; g2 ++ ) { | |
| for ( uint16_t b2 = 0 ; b2 < ( 1 << B_bits ) ; b2 ++ ) { | |
| uint16_t color2 = ( r2 << ( G_bits + B_bits ) ) | ( g2 << B_bits ) | b2; | |
| uint16_t r_expected = MIN( r1 + r2, ( 1 << R_bits ) - 1 ); | |
| uint16_t g_expected = MIN( g1 + g2, ( 1 << G_bits ) - 1 ); | |
| uint16_t b_expected = MIN( b1 + b2, ( 1 << B_bits ) - 1 ); | |
| uint16_t res = addRGB565( color1, color2 ); | |
| uint16_t r_result = ( res >> ( G_bits + B_bits ) ) & ( ( 1 << R_bits ) - 1 ); | |
| uint16_t g_result = ( res >> B_bits ) & ( ( 1 << G_bits ) - 1 ); | |
| uint16_t b_result = res & ( ( 1 << B_bits ) - 1 ); | |
| if ( r_result != r_expected || g_result != g_expected || b_result != b_expected ) { | |
| printf( "\nWrong Answer: (%d,%d,%d) (%d,%d,%d) -> (%d,%d,%d) but expected (%d,%d,%d)\n", | |
| r1, g1, b1, | |
| r2, g2, b2, | |
| r_result, g_result, b_result, | |
| r_expected, g_expected, b_expected | |
| ); | |
| return 1; | |
| } | |
| } | |
| } | |
| } | |
| } | |
| } | |
| } | |
| printf( "Succeeded!\n" ); | |
| return 0; | |
| } |
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