Copy ACIA driver to blkfs

We can get rid of acia.z80, but not of acia.fs yet, we still need it.
This commit is contained in:
Virgil Dupras 2020-04-23 12:42:41 -04:00
parent dd6ce1b8fe
commit a19376df6c
13 changed files with 132 additions and 62 deletions

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@ -3,7 +3,7 @@ MASTER INDEX
3 Usage 30 Dictionary
70 Implementation notes 100 Block editor
200 Z80 assembler 260 Cross compilation
280 Z80 boot code
280 Z80 boot code 350 ACIA driver

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ACIA driver
Manage I/O from an asynchronous communication interface adapter
(ACIA). provides "EMIT" to put c char on the ACIA as well as
an input buffer. You have to call "~ACIA" on interrupt for
this module to work well.
CONFIGURATION
ACIA_CTL: IO port for the ACIA's control registers
ACIA_IO: IO port for the ACIA's data registers
ACIA_MEM: Address in memory that can be used variables shared
with ACIA's native words. 8 bytes used.
Load z80 words with "352 LOAD" and Forth words with "357 LOAD".

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( Save ACIA conf )
ACIA_CTL
: ACIA_CTL [ LITN ] ;
ACIA_IO
: ACIA_IO [ LITN ] ;
ACIA_MEM
: ACIA_MEM [ LITN ] ;
( Memory layout
+0 ACIAR>
+2 ACIAW>
+4 ACIA(
+6 ACIA) )
353 356 LOADR

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(entry) ~ACIA
AF PUSHqq,
HL PUSHqq,
DE PUSHqq,
( Read our character from ACIA into our BUFIDX )
ACIA_CTL INAn,
0x01 ANDn, ( is ACIA rcv buf full? )
IFNZ,
( correct interrupt cause )
( +2 == ACIAW> )
ACIA_MEM 2+ LDHL(nn),
( is it == to ACIAR>? )
( +0 == ACIAR> )
DE ACIA_MEM LDdd(nn),
( carry cleared from ANDn above )
DE SBCHLss, ( cont. )

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IFNZ, ( buffer full? )
( no, continue )
DE ADDHLss, ( restore ACIAW> )
( buffer not full, let's write )
ACIA_IO INAn,
(HL) A LDrr,
( advance W> )
HL INCss,
( +2 == ACIAW> )
ACIA_MEM 2+ LD(nn)HL,
( +6 == ACIA) )
DE ACIA_MEM 6 + LDdd(nn),
DE SUBHLss,
( cont. )

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IFZ, ( end of buffer reached? )
( yes )
( +4 == ACIA( )
ACIA_MEM 4 + LDHL(nn),
( +2 == ACIAW> )
ACIA_MEM 2+ LD(nn)HL,
THEN,
THEN,
THEN,
DE POPqq,
HL POPqq,
AF POPqq,
EI,
RETI,

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0x20 CONSTANT ACIABUFSZ
( Points to ACIA buf )
: ACIA( [ ACIA_MEM 4 + LITN ] ;
( Points to ACIA buf end )
: ACIA) [ ACIA_MEM 6 + LITN ] ;
( Read buf pointer. Pre-inc )
: ACIAR> [ ACIA_MEM LITN ] ;
( Write buf pointer. Post-inc )
: ACIAW> [ ACIA_MEM 2 + LITN ] ;
( This means that if W> == R>, buffer is full.
If R>+1 == W>, buffer is empty. )
358 360 LOADR

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: ACIA$
H@ DUP DUP ACIA( ! ACIAR> !
1+ ACIAW> ! ( write index starts one position later )
ACIABUFSZ ALLOT
H@ ACIA) !
( setup ACIA
CR7 (1) - Receive Interrupt enabled
CR6:5 (00) - RTS low, transmit interrupt disabled.
CR4:2 (101) - 8 bits + 1 stop bit
CR1:0 (10) - Counter divide: 64 )
0b10010110 ACIA_CTL PC!
( setup interrupt )
0xc3 0x4e RAM+ C! ( c3==JP, 4e==INTJUMP )
['] ~ACIA 0x4f RAM+ !
(im1)
;

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: KEY
( inc then fetch )
ACIAR> @ 1+ DUP ACIA) @ = IF
DROP ACIA( @
THEN
( As long as R> == W>-1, it means that buffer is empty )
BEGIN DUP ACIAW> @ = NOT UNTIL
ACIAR> !
ACIAR> @ C@
;

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: EMIT
( As long at CTL bit 1 is low, we are transmitting. wait )
BEGIN ACIA_CTL PC@ 0x02 AND UNTIL
( The way is clear, go! )
ACIA_IO PC!
;

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( Save ACIA conf )
ACIA_CTL
: ACIA_CTL [ LITN ] ;
ACIA_IO
: ACIA_IO [ LITN ] ;
ACIA_MEM
: ACIA_MEM [ LITN ] ;
( Memory layout
+0 ACIAR>
+2 ACIAW>
+4 ACIA(
+6 ACIA)
)
(entry) ~ACIA
AF PUSHqq,
HL PUSHqq,
DE PUSHqq,
( Read our character from ACIA into our BUFIDX )
ACIA_CTL INAn,
0x01 ANDn, ( is ACIA rcv buf full? )
IFNZ,
( correct interrupt cause )
( +2 == ACIAW> )
ACIA_MEM 2+ LDHL(nn),
( is it == to ACIAR>? )
( +0 == ACIAR> )
DE ACIA_MEM LDdd(nn),
( carry cleared from ANDn above )
DE SBCHLss,
IFNZ, ( buffer full? )
( no, continue )
DE ADDHLss, ( restore ACIAW> )
( buffer not full, let's write )
ACIA_IO INAn,
(HL) A LDrr,
( advance W> )
HL INCss,
( +2 == ACIAW> )
ACIA_MEM 2+ LD(nn)HL,
( +6 == ACIA) )
DE ACIA_MEM 6 + LDdd(nn),
DE SUBHLss,
IFZ, ( end of buffer reached? )
( yes )
( +4 == ACIA( )
ACIA_MEM 4 + LDHL(nn),
( +2 == ACIAW> )
ACIA_MEM 2+ LD(nn)HL,
THEN,
THEN,
THEN,
DE POPqq,
HL POPqq,
AF POPqq,
EI,
RETI,

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@ -6,7 +6,7 @@ STAGE2 = $(EDIR)/stage2
EMUL = $(BASEDIR)/emul/hw/rc2014/classic
BOOTSRCS = conf.fs \
$(EDIR)/xcomp.fs \
$(BASEDIR)/drv/acia.z80 \
drvz80.fs \
$(BASEDIR)/drv/sdc.z80 \
$(FDIR)/icore.fs \
$(EDIR)/stop.fs

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352 LOAD ( acia.z80 )