mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-20 22:18:06 +11:00
393 lines
7.1 KiB
Forth
393 lines
7.1 KiB
Forth
( Z80 assembler )
|
|
|
|
: Z80AMEM+ 0x59 RAM+ @ + ;
|
|
|
|
( H@ offset at which we consider our PC 0. Used to compute
|
|
PC. To have a proper PC, call "H@ ORG !" at the beginning
|
|
of your assembly process. )
|
|
: ORG 0 Z80AMEM+ ;
|
|
|
|
( Labels are a convenient way of managing relative jump
|
|
calculations. Backward labels are easy. It is only a matter
|
|
or recording "HERE" and do subtractions. Forward labels
|
|
record the place where we should write the offset, and then
|
|
when we get to that point later on, the label records the
|
|
offset there.
|
|
|
|
To avoid using dict memory in compilation targets, we
|
|
pre-declare label variables here, which means we have a
|
|
limited number of it. For now, 4 ought to be enough. )
|
|
: L1 2 Z80AMEM+ ;
|
|
: L2 4 Z80AMEM+ ;
|
|
: L3 6 Z80AMEM+ ;
|
|
: L4 8 Z80AMEM+ ;
|
|
|
|
: Z80A$
|
|
( 59 == z80a's memory )
|
|
H@ 0x59 RAM+ !
|
|
10 ALLOT
|
|
;
|
|
|
|
( Splits word into msb/lsb, lsb being on TOS )
|
|
: SPLITB
|
|
256 /MOD SWAP
|
|
;
|
|
|
|
|
|
: PC H@ ORG @ - ;
|
|
|
|
( A, spits an assembled byte, A,, spits an assembled word
|
|
Both increase PC. To debug, change C, to .X )
|
|
: A, C, ;
|
|
: A,, SPLITB A, A, ;
|
|
|
|
( "r" register constants )
|
|
7 CONSTANT A
|
|
0 CONSTANT B
|
|
1 CONSTANT C
|
|
2 CONSTANT D
|
|
3 CONSTANT E
|
|
4 CONSTANT H
|
|
5 CONSTANT L
|
|
6 CONSTANT (HL)
|
|
|
|
( "ss" register constants )
|
|
0 CONSTANT BC
|
|
1 CONSTANT DE
|
|
2 CONSTANT HL
|
|
3 CONSTANT AF
|
|
3 CONSTANT SP
|
|
|
|
( "cc" condition constants )
|
|
0 CONSTANT CNZ
|
|
1 CONSTANT CZ
|
|
2 CONSTANT CNC
|
|
3 CONSTANT CC
|
|
4 CONSTANT CPO
|
|
5 CONSTANT CPE
|
|
6 CONSTANT CP
|
|
7 CONSTANT CM
|
|
|
|
( As a general rule, IX and IY are equivalent to spitting an
|
|
extra 0xdd / 0xfd and then spit the equivalent of HL )
|
|
: IX 0xdd A, HL ;
|
|
: IY 0xfd A, HL ;
|
|
: _ix+- 0xff AND 0xdd A, (HL) ;
|
|
: _iy+- 0xff AND 0xfd A, (HL) ;
|
|
: IX+ _ix+- ;
|
|
: IX- 0 -^ _ix+- ;
|
|
: IY+ _iy+- ;
|
|
: IY- 0 -^ _iy+- ;
|
|
|
|
: <<3 8 * ;
|
|
: <<4 16 * ;
|
|
|
|
( -- )
|
|
: OP1 CREATE C, DOES> C@ A, ;
|
|
0xf3 OP1 DI,
|
|
0xfb OP1 EI,
|
|
0xeb OP1 EXDEHL,
|
|
0xd9 OP1 EXX,
|
|
0x76 OP1 HALT,
|
|
0xe9 OP1 JP(HL),
|
|
0x12 OP1 LD(DE)A,
|
|
0x1a OP1 LDA(DE),
|
|
0x00 OP1 NOP,
|
|
0xc9 OP1 RET,
|
|
0x17 OP1 RLA,
|
|
0x07 OP1 RLCA,
|
|
0x1f OP1 RRA,
|
|
0x0f OP1 RRCA,
|
|
0x37 OP1 SCF,
|
|
|
|
( Relative jumps are a bit special. They're supposed to take
|
|
an argument, but they don't take it so they can work with
|
|
the label system. Therefore, relative jumps are an OP1 but
|
|
when you use them, you're expected to write the offset
|
|
afterwards yourself. )
|
|
|
|
0x18 OP1 JR,
|
|
0x38 OP1 JRC,
|
|
0x30 OP1 JRNC,
|
|
0x28 OP1 JRZ,
|
|
0x20 OP1 JRNZ,
|
|
0x10 OP1 DJNZ,
|
|
|
|
( r -- )
|
|
: OP1r
|
|
CREATE C,
|
|
DOES>
|
|
C@ ( r op )
|
|
SWAP ( op r )
|
|
<<3 ( op r<<3 )
|
|
OR A,
|
|
;
|
|
0x04 OP1r INCr,
|
|
0x05 OP1r DECr,
|
|
( also works for cc )
|
|
0xc0 OP1r RETcc,
|
|
|
|
( r -- )
|
|
: OP1r0
|
|
CREATE C,
|
|
DOES>
|
|
C@ ( r op )
|
|
OR A,
|
|
;
|
|
0x80 OP1r0 ADDr,
|
|
0x88 OP1r0 ADCr,
|
|
0xa0 OP1r0 ANDr,
|
|
0xb8 OP1r0 CPr,
|
|
0xb0 OP1r0 ORr,
|
|
0x90 OP1r0 SUBr,
|
|
0x98 OP1r0 SBCr,
|
|
0xa8 OP1r0 XORr,
|
|
|
|
( qq -- also works for ss )
|
|
: OP1qq
|
|
CREATE C,
|
|
DOES>
|
|
C@ ( qq op )
|
|
SWAP ( op qq )
|
|
<<4 ( op qq<<4 )
|
|
OR A,
|
|
;
|
|
0xc5 OP1qq PUSHqq,
|
|
0xc1 OP1qq POPqq,
|
|
0x03 OP1qq INCss,
|
|
0x0b OP1qq DECss,
|
|
0x09 OP1qq ADDHLss,
|
|
|
|
: ADDIXss, 0xdd A, ADDHLss, ;
|
|
: ADDIXIX, HL ADDIXss, ;
|
|
: ADDIYss, 0xfd A, ADDHLss, ;
|
|
: ADDIYIY, HL ADDIYss, ;
|
|
|
|
: _1rr
|
|
C@ ( rd rr op )
|
|
ROT ( rr op rd )
|
|
<<3 ( rr op rd<<3 )
|
|
OR OR A,
|
|
;
|
|
|
|
( rd rr )
|
|
: OP1rr
|
|
CREATE C,
|
|
DOES>
|
|
_1rr
|
|
;
|
|
0x40 OP1rr LDrr,
|
|
|
|
( ixy+- HL rd )
|
|
: LDIXYr,
|
|
( dd/fd has already been spit )
|
|
LDrr, ( ixy+- )
|
|
A,
|
|
;
|
|
|
|
( rd ixy+- HL )
|
|
: LDrIXY,
|
|
ROT ( ixy+- HL rd )
|
|
SWAP ( ixy+- rd HL )
|
|
LDIXYr,
|
|
;
|
|
|
|
: OP2 CREATE , DOES> @ 256 /MOD A, A, ;
|
|
0xedb1 OP2 CPIR,
|
|
0xed46 OP2 IM0,
|
|
0xed56 OP2 IM1,
|
|
0xed5e OP2 IM2,
|
|
0xed44 OP2 NEG,
|
|
0xed4d OP2 RETI,
|
|
|
|
( n -- )
|
|
: OP2n
|
|
CREATE C,
|
|
DOES>
|
|
C@ A, A,
|
|
;
|
|
0xd3 OP2n OUTnA,
|
|
0xdb OP2n INAn,
|
|
0xc6 OP2n ADDn,
|
|
0xe6 OP2n ANDn,
|
|
0xf6 OP2n Orn,
|
|
0xd6 OP2n SUBn,
|
|
|
|
( r n -- )
|
|
: OP2rn
|
|
CREATE C,
|
|
DOES>
|
|
C@ ( r n op )
|
|
ROT ( n op r )
|
|
<<3 ( n op r<<3 )
|
|
OR A, A,
|
|
;
|
|
0x06 OP2rn LDrn,
|
|
|
|
( b r -- )
|
|
: OP2br
|
|
CREATE C,
|
|
DOES>
|
|
0xcb A,
|
|
C@ ( b r op )
|
|
ROT ( r op b )
|
|
<<3 ( r op b<<3 )
|
|
OR OR A,
|
|
;
|
|
0xc0 OP2br SETbr,
|
|
0x80 OP2br RESbr,
|
|
0x40 OP2br BITbr,
|
|
|
|
( bitwise rotation ops have a similar sig )
|
|
( r -- )
|
|
: OProt
|
|
CREATE C,
|
|
DOES>
|
|
0xcb A,
|
|
C@ ( r op )
|
|
OR A,
|
|
;
|
|
0x10 OProt RLr,
|
|
0x00 OProt RLCr,
|
|
0x18 OProt RRr,
|
|
0x08 OProt RRCr,
|
|
0x20 OProt SLAr,
|
|
0x38 OProt SRLr,
|
|
|
|
( cell contains both bytes. MSB is spit as-is, LSB is ORed with r )
|
|
( r -- )
|
|
: OP2r
|
|
CREATE ,
|
|
DOES>
|
|
@ SPLITB SWAP ( r lsb msb )
|
|
A, ( r lsb )
|
|
SWAP <<3 ( lsb r<<3 )
|
|
OR A,
|
|
;
|
|
0xed41 OP2r OUT(C)r,
|
|
0xed40 OP2r INr(C),
|
|
|
|
( ss -- )
|
|
: OP2ss
|
|
CREATE C,
|
|
DOES>
|
|
0xed A,
|
|
C@ SWAP ( op ss )
|
|
<<4 ( op ss<< 4 )
|
|
OR A,
|
|
;
|
|
0x4a OP2ss ADCHLss,
|
|
0x42 OP2ss SBCHLss,
|
|
|
|
( dd nn -- )
|
|
: OP3ddnn
|
|
CREATE C,
|
|
DOES>
|
|
C@ ( dd nn op )
|
|
ROT ( nn op dd )
|
|
<<4 ( nn op dd<<4 )
|
|
OR A,
|
|
A,,
|
|
;
|
|
0x01 OP3ddnn LDddnn,
|
|
|
|
( nn -- )
|
|
: OP3nn
|
|
CREATE C,
|
|
DOES>
|
|
C@ A,
|
|
A,,
|
|
;
|
|
0xcd OP3nn CALLnn,
|
|
0xc3 OP3nn JPnn,
|
|
0x22 OP3nn LD(nn)HL,
|
|
0x2a OP3nn LDHL(nn),
|
|
|
|
( Specials )
|
|
|
|
( dd nn -- )
|
|
: LDdd(nn),
|
|
0xed A,
|
|
SWAP <<4 0x4b OR A,
|
|
A,,
|
|
;
|
|
|
|
( nn dd -- )
|
|
: LD(nn)dd,
|
|
0xed A,
|
|
<<4 0x43 OR A,
|
|
A,,
|
|
;
|
|
|
|
: JP(IX), IX DROP JP(HL), ;
|
|
: JP(IY), IY DROP JP(HL), ;
|
|
|
|
( 26 == next )
|
|
: JPNEXT, 26 JPnn, ;
|
|
|
|
: CODE
|
|
( same as CREATE, but with native word )
|
|
(entry)
|
|
( 23 == nativeWord )
|
|
23 C,
|
|
;
|
|
|
|
: ;CODE JPNEXT, ;
|
|
|
|
|
|
( Macros )
|
|
( clear carry + SBC )
|
|
: SUBHLss, A ORr, SBCHLss, ;
|
|
|
|
( Routines )
|
|
( 29 == chkPS )
|
|
: chkPS, 29 CALLnn, ;
|
|
|
|
( Flow
|
|
|
|
There are 2 label types: backward and forward. For each
|
|
type, there are two actions: set and write. Setting a label
|
|
is declaring where it is. It has to be performed at the
|
|
label's destination. Writing a label is writing its offset
|
|
difference to the binary result. It has to be done right
|
|
after a relative jump operation. Yes, labels are only for
|
|
relative jumps.
|
|
|
|
For backward labels, set happens before write. For forward
|
|
labels, write happen before set. The write operation writes
|
|
a dummy placeholder, and then the set operation writes the
|
|
offset at that placeholder's address.
|
|
|
|
Variable actions are expected to be called with labels in
|
|
front of them. Example, "L2 FSET"
|
|
|
|
About that "1 -": z80 relative jumps record "e-2", that is,
|
|
the offset that *counts the 2 bytes of the jump itself*.
|
|
Because we set the label *after* the jump OP1 itself, that's
|
|
1 byte that is taken care of. We still need to adjust by
|
|
another byte before writing the offset.
|
|
)
|
|
|
|
( Place BEGIN, where you want to jump back and AGAIN after
|
|
a relative jump operator. Just like BSET and BWR. )
|
|
: BEGIN, PC ;
|
|
: AGAIN, PC - 1- A, ;
|
|
|
|
: BSET PC SWAP ! ;
|
|
: BWR @ AGAIN, ;
|
|
( same as BSET, but we need to write a placeholder )
|
|
: FJR, PC 0 A, ;
|
|
: IFZ, JRNZ, FJR, ;
|
|
: IFNZ, JRZ, FJR, ;
|
|
: IFC, JRNC, FJR, ;
|
|
: IFNC, JRC, FJR, ;
|
|
: THEN,
|
|
DUP PC ( l l pc )
|
|
-^ 1- ( l off )
|
|
( warning: l is a PC offset, not a mem addr! )
|
|
SWAP ORG @ + ( off addr )
|
|
C!
|
|
;
|
|
: FWR BSET 0 A, ;
|
|
: FSET @ THEN, ;
|