emul: make stage2 load z80a from blkfs

This allows us to remove forth/z80a.fs. Another big step towards
self-hosting!

blk/001

@@ -2,6 +2,7 @@ MASTER INDEX
 
   3 Usage                      30 Dictionary
  70 Implementation notes      100 Block editor
+200 Z80 assembler
 
 
 

blk/200

@@ -0,0 +1,13 @@
+Z80 Assembler
+
+201 Guide                      208 Instructions list
+212 Loader                     213 Variables & consts
+215 Utils                      216 OP1
+218 OP1r                       220 OP1qq
+222 OP1rr                      224 OP2
+226 OP2n                       228 OP2rn
+230 OP2br                      232 OProt
+234 OP2r                       236 OP2ss
+238 OP3ddnn                    240 OP3nn
+242 Specials                   246 Flow
+

blk/201

@@ -0,0 +1,15 @@
+The following words allow you to assemble z80 binaries. Being
+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.
+
+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.
+

blk/202

@@ -0,0 +1,13 @@
+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.
+

blk/203

@@ -0,0 +1,14 @@
+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.
+

blk/208

@@ -0,0 +1,16 @@
+Instructions list
+
+r => A B C D E H L (HL)
+ss/qq => BC DE HL AF/SP
+cc => CNZ CZ CNC CC CPO CPE CP CM
+
+LD [rr, rn, ddnn, (nn)HL, HL(nn), dd(nn), (nn)dd, rIXY, IXYr,
+    (DE)A, A(DE)]
+ADD [r, n, HLss, IXss, IXIX, IYss, IYIY]
+ADC [r, HLss]
+CP  [r]
+SBC [r, HLss]
+SUB [r, n]
+PUSH [qq]  POP [qq]
+INC [r, ss]            DEC [r, ss]
+AND [r, n] OR [r, n]   XOR [r, n]                       (cont.)

blk/209

@@ -0,0 +1,11 @@
+(cont.)
+OUT [nA, (C)r]         IN [An, r(C)]
+SET [br]   RES [br]    BIT [br]
+RL [r]     RLC [r]     SLA [r]     RLA         RLCA
+RR [r]     RRC [r]     SRL [r]     RRA         RRCA
+CALL [nn]  DJNZ
+JP [nn, (HL), (IX), (IY)]
+JR [, Z, NZ, C, NC]
+
+DI         EI          EXDEHL      EXX         HALT
+NOP        RET         SCF

blk/212

@@ -0,0 +1,8 @@
+( 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 244 LOAD 246 LOAD 247 LOAD

blk/213

@@ -0,0 +1,9 @@
+: Z80AMEM+ 0x59 RAM+ @ + ;
+: ORG 0 Z80AMEM+ ;
+: L1 2 Z80AMEM+ ; : L2 4 Z80AMEM+ ;
+: L3 6 Z80AMEM+ ; : L4 8 Z80AMEM+ ;
+: 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 ;
+: CNZ 0 ; : CZ 1 ; : CNC 2 ; : CC 3 ;
+: CPO 4 ; : CPE 5 ; : CP 6 ; : CM 7 ;

blk/215

@@ -0,0 +1,16 @@
+( 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, ;
+: <<3 8 * ;    : <<4 16 * ;
+( 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+- ;

blk/216

@@ -0,0 +1,10 @@
+: 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,
+

blk/217

@@ -0,0 +1,11 @@
+( 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,                   0x10 OP1 DJNZ,
+0x38 OP1 JRC,                  0x30 OP1 JRNC,
+0x28 OP1 JRZ,                  0x20 OP1 JRNZ,
+
+

blk/218

@@ -0,0 +1,10 @@
+( r -- )
+: OP1r
+    CREATE C,
+    DOES>
+    C@              ( r op )
+    SWAP            ( op r )
+    <<3             ( op r<<3 )
+    OR A,
+;
+0x04 OP1r INCr,                0x05 OP1r DECr,

blk/219

@@ -0,0 +1,13 @@
+( 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,

blk/220

@@ -0,0 +1,15 @@
+( 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, ;

blk/222

@@ -0,0 +1,14 @@
+: _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,

blk/223

@@ -0,0 +1,13 @@
+( 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,
+;

blk/224

@@ -0,0 +1,7 @@
+: 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,

blk/226

@@ -0,0 +1,13 @@
+( 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,
+

blk/228

@@ -0,0 +1,11 @@
+( 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,
+

blk/230

@@ -0,0 +1,14 @@
+( 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,
+

blk/232

@@ -0,0 +1,16 @@
+( 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,
+

blk/234

@@ -0,0 +1,14 @@
+( 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),
+

blk/236

@@ -0,0 +1,12 @@
+( ss -- )
+: OP2ss
+    CREATE C,
+    DOES>
+    0xed A,
+    C@ SWAP         ( op ss )
+    <<4             ( op ss<< 4 )
+    OR A,
+;
+0x4a OP2ss ADCHLss,
+0x42 OP2ss SBCHLss,
+

blk/238

@@ -0,0 +1,11 @@
+( 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,

blk/240

@@ -0,0 +1,11 @@
+( nn -- )
+: OP3nn
+    CREATE C,
+    DOES>
+    C@ A,
+    A,,
+;
+0xcd OP3nn CALLnn,
+0xc3 OP3nn JPnn,
+0x22 OP3nn LD(nn)HL,
+0x2a OP3nn LDHL(nn),

blk/242

@@ -0,0 +1,16 @@
+( 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), ;

blk/243

@@ -0,0 +1,14 @@
+( 26 == next )
+: JPNEXT, 26 JPnn, ;
+( 29 == chkPS )
+: chkPS, 29 CALLnn, ;
+
+: CODE
+    ( same as CREATE, but with native word )
+    (entry)
+    ( 23 == nativeWord )
+    23 C,
+;
+
+: ;CODE JPNEXT, ;
+

blk/244

@@ -0,0 +1,3 @@
+( Macros )
+( clear carry + SBC )
+: SUBHLss, A ORr, SBCHLss, ;

blk/246

@@ -0,0 +1,13 @@
+( 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, ;

blk/247

@@ -0,0 +1,9 @@
+: 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, ;

emul/Makefile

@@ -8,8 +8,7 @@ BOOTSRCS = ./forth/conf.fs \
 	../forth/icore.fs \
 	./forth/xstop.fs
 
-FORTHSRCS = core.fs cmp.fs print.fs str.fs parse.fs readln.fs fmt.fs z80a.fs \
-	link.fs blk.fs
+FORTHSRCS = core.fs cmp.fs print.fs str.fs parse.fs readln.fs fmt.fs blk.fs
 FORTHSRC_PATHS = ${FORTHSRCS:%=../forth/%} forth/run.fs
 OBJS = emul.o libz80/libz80.o
 SLATEST = ../tools/slatest
@@ -58,12 +57,15 @@ forth/forth1.bin: forth/core.bin $(SLATEST)
 forth/forth1-bin.h: forth/forth1.bin $(BIN2C)
 	$(BIN2C) KERNEL < forth/forth1.bin > $@
 
-forth/stage2: forth/stage.c $(OBJS) forth/forth1-bin.h 
+forth/stage2: forth/stage.c $(OBJS) forth/forth1-bin.h forth/blkfs-bin.h
 	$(CC) -DSTAGE2 forth/stage.c $(OBJS) -o $@
 
 blkfs: $(BLKPACK)
 	$(BLKPACK) ../blk > $@
 
+forth/blkfs-bin.h: blkfs $(BIN2C)
+	$(BIN2C) BLKFS < blkfs > $@
+
 forth/forth: forth/forth.c $(OBJS) forth/forth1-bin.h blkfs
 	$(CC) forth/forth.c $(OBJS) -o $@
 

emul/forth/conf.fs

@@ -1,2 +1,3 @@
+212 LOAD  ( z80 assembler )
 0xe800 CONSTANT RAMSTART
 0xf000 CONSTANT RS_ADDR

emul/forth/run.fs

@@ -18,7 +18,6 @@
     ['] EFS@ BLK@* !
     ['] EFS! BLK!* !
     RDLN$
-    Z80A$
     LIT< _sys [entry]
     INTERPRET
 ;

emul/forth/stage.c

@@ -4,6 +4,7 @@
 #include "../emul.h"
 #ifdef STAGE2
 #include "forth1-bin.h"
+#include "blkfs-bin.h"
 #else
 #include "forth0-bin.h"
 #endif
@@ -34,6 +35,10 @@ trouble of compiling defs to binary.
 // To know which part of RAM to dump, we listen to port 2, which at the end of
 // its compilation process, spits its HERE addr to port 2 (MSB first)
 #define HERE_PORT 0x02
+// Port for block reads. Write 2 bytes, MSB first, on that port and then
+// read 1024 bytes from the DATA port.
+#define BLK_PORT 0x03
+#define BLKDATA_PORT 0x04
 
 static int running;
 // We support double-pokes, that is, a first poke to tell where to start the
@@ -41,6 +46,8 @@ static int running;
 // then ending HERE and we start at sizeof(KERNEL).
 static uint16_t start_here = 0;
 static uint16_t end_here = 0;
+static uint16_t blkid = 0;
+static unsigned int blkpos = 0;
 
 static uint8_t iord_stdio()
 {
@@ -68,6 +75,20 @@ static void iowr_here(uint8_t val)
     end_here |= val;
 }
 
+#ifdef STAGE2
+static void iowr_blk(uint8_t val)
+{
+    blkid <<= 8;
+    blkid |= val;
+    blkpos = blkid * 1024;
+}
+
+static uint8_t iord_blkdata()
+{
+    return BLKFS[blkpos++];
+}
+#endif
+
 int main(int argc, char *argv[])
 {
     Machine *m = emul_init();
@@ -75,6 +96,10 @@ int main(int argc, char *argv[])
     m->iord[STDIO_PORT] = iord_stdio;
     m->iowr[STDIO_PORT] = iowr_stdio;
     m->iowr[HERE_PORT] = iowr_here;
+#ifdef STAGE2
+    m->iowr[BLK_PORT] = iowr_blk;
+    m->iord[BLKDATA_PORT] = iord_blkdata;
+#endif
     // initialize memory
     for (int i=0; i<sizeof(KERNEL); i++) {
         m->mem[i] = KERNEL[i];

forth/z80a.fs

@@ -1,392 +0,0 @@
-( 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, ;