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z80a: add BIN( parameter

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Will be useful for assembling binaries for the TRS-80 which can't start
at addr 0.
This commit is contained in:
Virgil Dupras 2020-04-27 15:04:37 -04:00
parent ee79df225e
commit 295b4b6e0a
22 changed files with 72 additions and 61 deletions
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17
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@ -3,13 +3,14 @@ Forth words, opcode assembly is a bit different than with a
typical assembler. For example, what would traditionally be
"ld a, b" would become "A B LDrr,".
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.
BIN( is the addr at which the compiled binary will live. It is
often 0.
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.
ORG is H@ offset at which we begin spitting binary. Used to
compute PC. To have a proper PC, call "H@ ORG !" at the
beginning of your assembly process. PC is H@ - ORG + BIN(.
(cont.)

17
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@ -1,13 +1,16 @@
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.
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.
(cont.)

18
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@ -1,14 +1,16 @@
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.
(cont.)

10
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@ -0,0 +1,10 @@
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.

10
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@ -1,8 +1,2 @@
( 59 == z80a's memory )
H@ 0x59 RAM+ !
10 ALLOT
213 LOAD 215 LOAD 216 LOAD 217 LOAD 218 LOAD 219 LOAD
220 LOAD 222 LOAD 223 LOAD 224 LOAD 226 LOAD 228 LOAD
230 LOAD 232 LOAD 234 LOAD 236 LOAD 238 LOAD 240 LOAD
242 LOAD 243 LOAD 246 LOAD 247 LOAD 249 LOAD
213 LOAD Z80A$
215 249 LOADR

6
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@ -1,7 +1,9 @@
: Z80AMEM+ 0x59 RAM+ @ + ;
: ORG 0 Z80AMEM+ ;
: L1 2 Z80AMEM+ ; : L2 4 Z80AMEM+ ;
: L3 6 Z80AMEM+ ; : L4 8 Z80AMEM+ ;
: BIN( 2 Z80AMEM+ ;
: L1 4 Z80AMEM+ ; : L2 6 Z80AMEM+ ;
: L3 8 Z80AMEM+ ; : L4 10 Z80AMEM+ ;
: Z80A$ H@ 0x59 RAM+ ! 12 ALLOT 0 BIN( ! ;
: A 7 ; : B 0 ; : C 1 ; : D 2 ;
: E 3 ; : H 4 ; : L 5 ; : (HL) 6 ;
: BC 0 ; : DE 1 ; : HL 2 ; : AF 3 ; : SP AF ;

2
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@ -2,7 +2,7 @@
: SPLITB
256 /MOD SWAP
;
: PC H@ ORG @ - ;
: PC H@ ORG @ - BIN( @ + ;
( 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, ;

17
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@ -1,16 +1,15 @@
: JPccnn, SWAP <<3 0xc2 OR A, A,, ;
: BCALL, BIN( @ + CALLnn, ;
: BJP, BIN( @ + JPnn, ;
: BJPcc, BIN( @ + JPccnn, ;
( 26 == next )
: JPNEXT, 26 JPnn, ;
( 29 == chkPS )
: chkPS, 29 CALLnn, ;
: JPNEXT, 26 BJP, ; ( 26 == next )
: CODE
( same as CREATE, but with native word )
: chkPS, 29 BCALL, ; ( 29 == chkPS )
: CODE ( same as CREATE, but with native word )
(entry)
( 23 == nativeWord )
23 C,
23 C, ( 23 == nativeWord )
;
: ;CODE JPNEXT, ;

2
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@ -4,3 +4,5 @@
: PUSH0, BC 0 LDddnn, BC PUSHqq, ;
: PUSH1, BC 1 LDddnn, BC PUSHqq, ;
: PUSHZ, BC 0 LDddnn, IFZ, BC INCss, THEN, BC PUSHqq, ;
: HLZ, A H LDrr, L ORr, ;
: DEZ, A D LDrr, E ORr, ;

2
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@ -6,7 +6,7 @@
4 A,
H@ XCURRENT ! ( set current tip of dict, 0x42 )
0x17 A, ( nativeWord )
0x14 CALLnn, ( popRS )
0x14 BCALL, ( popRS )
HL PUSHqq, IY POPqq, ( --> IP )
JPNEXT,

3
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@ -1,8 +1,7 @@
CODE (?br) ( 0x67 )
HL POPqq,
chkPS,
A H LDrr,
L ORr,
HLZ,
JRZ, L2 BWR ( BR + 2. False, branch )
( True, skip next 2 bytes and don't branch )
IY INCss,

2
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@ -12,5 +12,5 @@ PC ORG @ 1 + ! ( main )
( LATEST is a label to the latest entry of the dict. It is
written at offset 0x08 by the process or person building
Forth. )
0x08 LDHL(nn),
BIN( @ 0x08 + LDHL(nn),
RAMSTART 0x02 + LD(nn)HL, ( RAM+02 == CURRENT cont. )

4
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@ -1,4 +1,4 @@
EXDEHL,
HL L1 @ LDddnn,
0x03 CALLnn, ( 03 == find )
0x33 JPnn, ( 33 == execute )
0x03 BCALL, ( 03 == find )
0x33 BJP, ( 33 == execute )

4
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@ -1,8 +1,7 @@
( DE contains prev offset )
HL POPqq, ( <-- lvl 2 )
( HL is prev field's addr. Is offset zero? )
A D LDrr,
E ORr,
DEZ,
IFNZ,
( get absolute addr from offset )
( carry cleared from "or e" )
@ -13,4 +12,5 @@
JRNZ, AGAIN, ( inner-B292, try to match again )
( Z set? end of dict, unset Z )
( cont. )

4
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@ -2,6 +2,6 @@
L2 BSET ( abortUnderflow )
HL PC 7 - LDddnn,
DE RAMSTART 0x02 + LDdd(nn), ( RAM+02 == CURRENT )
0x03 CALLnn, ( find )
0x33 JPnn, ( 33 == execute )
0x03 BCALL, ( find )
0x33 BJP, ( 33 == execute )

2
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@ -3,7 +3,7 @@ PC ORG @ 0x1b + ! ( next )
we jump to current IP, but we also take care of increasing
it by 2 before jumping. )
( Before we continue: are stacks within bounds? )
0x1d CALLnn, ( chkPS )
0x1d BCALL, ( chkPS )
( check RS )
IX PUSHqq, HL POPqq,
DE RS_ADDR LDddnn,

2
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@ -3,7 +3,7 @@ PC ORG @ 0x34 + ! ( execute )
( DE points to wordref )
EXDEHL,
E (HL) LDrr,
D 0 LDrn,
D BIN( @ 256 / LDrn,
EXDEHL,
( HL points to code pointer )
DE INCss,

2
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@ -4,7 +4,7 @@ PC ORG @ 0x0f + ! ( compiledWord )
2. Set new IP to the second atom of the list
3. Execute the first atom of the list. )
IY PUSHqq, HL POPqq, ( <-- IP )
0x11 CALLnn, ( 11 == pushRS )
0x11 BCALL, ( 11 == pushRS )
EXDEHL, ( HL points to PFA )
( While we increase, dereference into DE for execute call
later. )

3
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@ -1,8 +1,7 @@
CODE NOT
HL POPqq,
chkPS,
A L LDrr,
H ORr,
HLZ,
PUSHZ,
;CODE

4
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@ -2,12 +2,12 @@ CODE >R
HL POPqq,
chkPS,
( 17 == pushRS )
17 CALLnn,
17 BCALL,
;CODE
CODE R>
( 20 == popRS )
20 CALLnn,
20 BCALL,
HL PUSHqq,
;CODE

2
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@ -3,7 +3,7 @@ CODE _find ( cur w -- a f )
DE POPqq, ( cur )
chkPS,
( 3 == find )
3 CALLnn,
3 BCALL,
IFNZ,
( not found )
HL PUSHqq,

BIN
emul/stage0.bin
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