collapseos/forth/z80c.fs
2020-03-27 11:36:58 -04:00

232 lines
3.7 KiB
Forth

( Core words in z80. This requires a full Forth interpreter
to run, but is also necessary for core.fs. This means that
it needs to be compiled from a prior bootstrapped binary.
This stage is tricky due to the fact that references in
Forth are all absolute, except for prev word refs. This
means that there are severe limitations to the kind of code
you can put here.
You shouldn't define any word with reference to other words.
This means no regular definition. You can, however, execute
any word from our high level Forth, as long as it doesn't
spit word references.
ROUTINE stuff is fine. It's not supposed to change.
These restrictions are temporary, I'll figure something out
so that we can end up fully bootstrap Forth from within
itself.
Oh, also: KEY and EMIT are not defined here. There're
expected to be defined in platform-specific code.
)
( a b c -- b c a )
CODE ROT
HL POPqq, ( C )
DE POPqq, ( B )
BC POPqq, ( A )
chkPS,
DE PUSHqq, ( B )
HL PUSHqq, ( C )
BC PUSHqq, ( A )
;CODE
( a b -- a b a b )
CODE 2DUP
HL POPqq, ( B )
DE POPqq, ( A )
chkPS,
DE PUSHqq, ( A )
HL PUSHqq, ( B )
DE PUSHqq, ( A )
HL PUSHqq, ( B )
;CODE
( a b c d -- a b c d a b )
CODE 2OVER
HL POPqq, ( D )
DE POPqq, ( C )
BC POPqq, ( B )
IY POPqq, ( A )
chkPS,
IY PUSHqq, ( A )
BC PUSHqq, ( B )
DE PUSHqq, ( C )
HL PUSHqq, ( D )
IY PUSHqq, ( A )
BC PUSHqq, ( B )
;CODE
( a b c d -- c d a b )
CODE 2SWAP
HL POPqq, ( D )
DE POPqq, ( C )
BC POPqq, ( B )
IY POPqq, ( A )
chkPS,
DE PUSHqq, ( C )
HL PUSHqq, ( D )
IY PUSHqq, ( A )
BC PUSHqq, ( B )
;CODE
CODE AND
HL POPqq,
DE POPqq,
chkPS,
A E LDrr,
L ANDr,
L A LDrr,
A D LDrr,
H ANDr,
H A LDrr,
HL PUSHqq,
;CODE
CODE OR
HL POPqq,
DE POPqq,
chkPS,
A E LDrr,
L ORr,
L A LDrr,
A D LDrr,
H ORr,
H A LDrr,
HL PUSHqq,
;CODE
CODE XOR
HL POPqq,
DE POPqq,
chkPS,
A E LDrr,
L XORr,
L A LDrr,
A D LDrr,
H XORr,
H A LDrr,
HL PUSHqq,
;CODE
CODE -
DE POPqq,
HL POPqq,
chkPS,
A ORr,
DE SBCHLss,
HL PUSHqq,
;CODE
CODE *
DE POPqq,
BC POPqq,
chkPS,
( DE * BC -> DE (high) and HL (low) )
HL 0 LDddnn,
A 0x10 LDrn,
( loop )
HL ADDHLss,
E RLr,
D RLr,
6 JRNCe, ( noinc )
BC ADDHLss,
3 JRNCe, ( noinc )
DE INCss,
( noinc )
A DECr,
-12 JRNZe, ( loop )
HL PUSHqq,
;CODE
( Borrowed from http://wikiti.brandonw.net/ )
( Divides AC by DE and places the quotient in AC and the
remainder in HL )
CODE /MOD
DE POPqq,
BC POPqq,
chkPS,
A B LDrr,
B 16 LDrn,
HL 0 LDddnn,
( loop )
SCF,
C RLr,
RLA,
HL ADCHLss,
DE SBCHLss,
4 JRNCe, ( skip )
DE ADDHLss,
C DECr,
( skip )
-12 DJNZe, ( loop )
B A LDrr,
HL PUSHqq,
BC PUSHqq,
;CODE
CODE C!
HL POPqq,
DE POPqq,
chkPS,
E LD(HL)r,
;CODE
CODE C@
HL POPqq,
chkPS,
L LDr(HL),
H 0 LDrn,
HL PUSHqq,
;CODE
CODE PC!
BC POPqq,
HL POPqq,
chkPS,
L OUT(C)r,
;CODE
CODE PC@
BC POPqq,
chkPS,
H 0 LDrn,
L INr(C),
HL PUSHqq,
;CODE
CODE I
L 0 IX+ LDrIXY,
H 1 IX+ LDrIXY,
HL PUSHqq,
;CODE
CODE I'
L 2 IX- LDrIXY,
H 1 IX- LDrIXY,
HL PUSHqq,
;CODE
CODE J
L 4 IX- LDrIXY,
H 3 IX- LDrIXY,
HL PUSHqq,
;CODE
CODE >R
HL POPqq,
chkPS,
( JUMPTBL+0 == pushRS )
ROUTINE J CALLnn,
;CODE
CODE R>
( JUMPTBL+3 == popRS )
ROUTINE J 3 + CALLnn,
HL PUSHqq,
;CODE