Routines |
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BREAK_KEY | 1F54 | LD A,$7F | Form the port address +7FFE and read in a byte. | |
1F56 | IN A,($FE) | |||
1F58 | RRA | Examine only bit 0 by shifting it into the carry position. | ||
1F59 | RET C | Return if the BREAK key is not being pressed. | ||
1F5A | LD A,$FE | Form the port address +FEFE and read in a byte. | ||
1F5C | IN A,($FE) | |||
1F5E | RRA | Again examine bit 0. | ||
1F5F | RET | Return with carry reset if both keys are being pressed. |
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