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15 lines
532 B
Plaintext
15 lines
532 B
Plaintext
0x80 CONSTANT ACIA_CTL ( IO port for ACIA's control register )
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0x81 CONSTANT ACIA_IO ( IO port for ACIA's data registers )
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0x20 CONSTANT ACIA_BUFSZ ( SZ-1 must be a mask )
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( Address in memory that can be used variables shared
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with ACIA's native words. 4 bytes used. )
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CREATE ACIA_MEM SYSVARS 0x70 + ,
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( Points to ACIA buf )
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: ACIA( ACIA_MEM @ 2+ ;
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( Read buf idx Pre-inc )
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: ACIAR> ACIA_MEM @ ;
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( Write buf idx Post-inc )
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: ACIAW> ACIA_MEM @ 1+ ;
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( This means that if W> == R>, buffer is full.
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If R>+1 == W>, buffer is empty. )
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