z: initial commit from qkumba

basic/z/Makefile

@@ -0,0 +1,30 @@
+include ../../Makefile.inc
+
+DOS33 = ../../utils/dos33fs-utils/dos33
+TOKENIZE = ../../utils/asoft_basic-utils/tokenize_asoft
+EMPTY_DISK = ../../empty_disk/empty.dsk
+
+all:	z.dsk z
+
+z.dsk:	HELLO
+	cp $(EMPTY_DISK) z.dsk
+	$(DOS33) -y z.dsk SAVE A HELLO
+
+####
+
+HELLO:	hello.bas
+	$(TOKENIZE) < hello.bas > HELLO
+####
+
+z:	z.o
+	$(CC) $(LFLAGS) -o z z.o
+
+z.o:	z.c
+	$(CC) $(CFLAGS) -c z.c
+
+####
+
+
+clean:
+	rm -f *~ *.o *.lst HELLO z
+

basic/z/README

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+Executable ASCII decoding.
+Here's the encoder source.
+It requires a 65C02, though, to save one byte.  I would like to fix
+that somehow.
+
+How it works:
+
+On entry:
+- X=$9D;
+- Y is the low byte of the CALL target;
+- carry is clear;
+- $7D-7E is $800;
+- $B8-B9 points to the token after the CALL;
+- $73-74 points to $9600;
+- $6F-70 points to $9600.
+
+        dex                     ca              *
+        dex                     ca              *
+        dex                     ca              *
+        dex                     ca              *
+        dex                     ca              *
+        dex                     ca              *
+
+Sets X to $97, so we can use it later.
+
+        dey                     88              GR
+
+Skip the opening quote (it's read backwards) in the 6-bit table.
+
+--      inc     $b8             e6      b8      ASC     DEF
+
+Skip the opening quote in the 2-bit table.
+
+        lda     ($21,x)         a1      21      POP     !
+
+Read from 2-bit table (at $B8).
+
+        adc     #$5c            69      5c      i       \
+
+Move into $80+ range, guarantees a bit is set so we don't exit early.
+
+        sta     $30             85      30      DEL     0
+
+Save for later.
+
+-       dey                     88              GR
+        lda     ($7d),y         b1      7d      RETURN  }
+
+Read from 6-bit table.
+
+        adc     #$5c            69      5d      i       \
+
+Move into $80+ range, always sets V flag because bit 6 and bit 7 are
+inverted in our data (V will be cleared when we read a value < $24,
+specifically the closing quote).
+        lsr     $30             46      30      F       0
+        ror                     6a              j
+        ror                     6a              j
+        ror                     6a              j
+        ror                     6a              j
+        ror                     6a              j
+        ror                     6a              j
+        ror                     6a              j
+        lsr     $30             46      30      F       0
+        ror                     6a              j
+
+2-bit table carries bits 7 and 0.
+
+        sta     ($dc,x)         81      dc      FOR     LOG
+
+Write through ($73).
+
+        inc     $73             e6      73      ASC     s
+
+Move next.
+
+        lda     $30             a5      30      ONERR   0
+        dec                     3a              :
+        dec                     3a              :
+        bne     -               d0      e5      =       VAL
+
+Loop while a bit is set.
+
+        bvs     --              70      db      p       RND
+
+Loop while our data are read.
+
+        jmp     ($6f)           6c      6f      l       o
+
+Jump $9600.

basic/z/hello.bas

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+5 HOME
+10 PRINT CHR$(4);"CATALOG"

basic/z/z.c

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+#include <fcntl.h>
+#include <io.h>
+#include <stdio.h>
+#include <string.h>
+
+static unsigned char decoder[] = "\"******GRASCDEFPOP!i\\DEL0GRRETURN}i\\F0jjjjjjjF0jFORLOGASCsONERR0::=VALpRNDlo";
+
+void main(int argc, char *argv[])
+{
+	int i, l, j, b2, b6;
+	unsigned char b[150];
+	unsigned char bb2[150];
+	unsigned char bb6[150];
+	unsigned char call[10];
+
+	memset(b, 0, sizeof(b));
+	i = open(argv[1], O_RDONLY | O_BINARY);
+	l = read(i, b, sizeof(b));
+	close(i);
+
+	j = 0;
+	b2 = 0;
+	b6 = sizeof(bb6);
+
+	do
+	{
+		unsigned char c;
+
+		if (!(j % 3))
+		{
+			c = ((((b[j + 0] >> 6) & 2) + (b[j + 0] & 1)) << 0)
+	 		  + ((((b[j + 1] >> 6) & 2) + (b[j + 1] & 1)) << 2)
+			  + ((((b[j + 2] >> 6) & 2) + (b[j + 2] & 1)) << 4)
+			  + 0x23;
+
+			bb2[b2++] = c + (int) !j;
+		}
+
+		c = ((b[j] >> 1) & 0x3f) + 0x23 + (int) !(j % 3);
+
+		bb6[--b6] = c;
+	}
+	while (++j < l);
+
+	sprintf(call, "0CALL%d\"", 2049+10+b2+6+(int)sizeof(bb6)-b6+1);
+	i = open("out", O_WRONLY | O_BINARY | O_CREAT | O_TRUNC, 0x80);
+	write(i, call, strlen(call));
+	write(i, bb2, b2);
+	write(i, "\r\n1\"", sizeof("\r\n1\"")-1);
+	write(i, bb6 + b6, sizeof(bb6) - b6);
+	write(i, decoder, sizeof(decoder)-1);
+	close(i);
+}