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collapseos/arch/z80/rc2014/blk/602

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rc2014: add a declaration part to ACIA drivers Driver configuration don't need their own words at runtime, we only need to compile them as literals when compiling words. Now that we have this "declaration blocks" pattern emerging, it seems like a good idea to take advantage of this in drivers, both for simplifying the xcomp unit and to make final binary slimmer.
2020-06-29 07:30:01 +10:00
0x80 CONSTANT ACIA_CTL ( IO port for ACIA's control register )
0x81 CONSTANT ACIA_IO ( IO port for ACIA's data registers )
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler.
2020-08-15 12:51:27 +10:00
0x20 CONSTANT ACIA_BUFSZ ( SZ-1 must be a mask )
rc2014: add a declaration part to ACIA drivers Driver configuration don't need their own words at runtime, we only need to compile them as literals when compiling words. Now that we have this "declaration blocks" pattern emerging, it seems like a good idea to take advantage of this in drivers, both for simplifying the xcomp unit and to make final binary slimmer.
2020-06-29 07:30:01 +10:00
( Address in memory that can be used variables shared
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler.
2020-08-15 12:51:27 +10:00
with ACIA's native words. 4 bytes used. )
Rename RAMSTART to SYSVARS It's more descriptive this way. Also, I'll soon add a new HERESTART config.
2020-06-29 08:49:30 +10:00
CREATE ACIA_MEM SYSVARS 0x70 + ,
rc2014: add a declaration part to ACIA drivers Driver configuration don't need their own words at runtime, we only need to compile them as literals when compiling words. Now that we have this "declaration blocks" pattern emerging, it seems like a good idea to take advantage of this in drivers, both for simplifying the xcomp unit and to make final binary slimmer.
2020-06-29 07:30:01 +10:00
( Points to ACIA buf )
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler.
2020-08-15 12:51:27 +10:00
: ACIA( ACIA_MEM @ 2+ ;
( Read buf idx Pre-inc )
rc2014: add a declaration part to ACIA drivers Driver configuration don't need their own words at runtime, we only need to compile them as literals when compiling words. Now that we have this "declaration blocks" pattern emerging, it seems like a good idea to take advantage of this in drivers, both for simplifying the xcomp unit and to make final binary slimmer.
2020-06-29 07:30:01 +10:00
: ACIAR> ACIA_MEM @ ;
acia: simplify driver The previous approach of maintaining R> and W> pointers was conceptually simple, but made INT handler code actually quite complex. Now, we maintain indexes instead. It's much easier to perform bounds checks and to compare for equality, something we have to do quick in the INT handler.
2020-08-15 12:51:27 +10:00
( Write buf idx Post-inc )
: ACIAW> ACIA_MEM @ 1+ ;
rc2014: add a declaration part to ACIA drivers Driver configuration don't need their own words at runtime, we only need to compile them as literals when compiling words. Now that we have this "declaration blocks" pattern emerging, it seems like a good idea to take advantage of this in drivers, both for simplifying the xcomp unit and to make final binary slimmer.
2020-06-29 07:30:01 +10:00
( This means that if W> == R>, buffer is full.
If R>+1 == W>, buffer is empty. )
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