bin2bac: Add program to convert an assembly program to a .BAC file

A fairly compact way to store an assembly program, comparable in
overhead to an .ABS file.

3 files changed, 159 insertions, 1 deletions

diff --git a/data/Makefile b/data/Makefile
index 5f1fba0..2dba4e2 100644
--- a/data/Makefile
+++ b/data/Makefile
@@ -9,7 +9,7 @@ Z80ASM  = ../tools/z80asm/z80asm
 
 all :	keyboard.mif abc80rom.bin basic80.mif \
 	mmu.mif chargen.mif videoram.mif fgcol.mif sddrom.mif \
-	abcsefi.bas abcdkno.bas abcintl.bas cpm.bas cpm.abs
+	abcsefi.bas abcdkno.bas abcintl.bas cpm.bas cpm.abs cpm.bac
 
 abc80rom.bin : buildrom.pl abcbasic.rom ufddos.bin printer.bin
 	$(PERL) buildrom.pl $@ 32768 \
@@ -67,6 +67,9 @@ cpm.bas: cpm.bin
 cpm.abs: cpm.bin
 	$(PERL) bin2abs.pl $< 32768 > $@ || ( rm -f $@ ; exit 1 )
 
+cpm.bac: cpm.bin
+	$(PERL) bin2bac.pl $< 32768 32768 > $@ || ( rm -f $@ ; exit 1 )
+
 .bin.bas:
 	$(PERL) bin2poke.pl $< 16384 100 RETURN | cat charpoke.bah - > $@ \
 		|| ( rm -f $@ ; exit 1 )
diff --git a/data/bacldr.asm b/data/bacldr.asm
new file mode 100644
index 0000000..2d0e43b
--- /dev/null
+++ b/data/bacldr.asm
@@ -0,0 +1,45 @@
+	org 0			; This code must be position-independent
+
+BOFA:	equ 65052
+offset:	equ 0xeeee		; Length of the BASIC prefix
+
+	ld hl,(BOFA)
+	ld de,offset
+	add hl,de
+
+	ld b,0
+
+	; Get data block length
+loop:
+	ld a,-10
+	add (hl)
+	jr nc,run		; End of file marked by an empty REM
+
+	; Skip length byte + line number (2 bytes) + string opcode (3 bytes)
+	ld c,6
+	add hl,bc
+
+	; Load address
+	ld e,(hl)
+	inc hl
+	ld d,(hl)
+	inc hl
+
+	; Copy remaining data
+	ld c,a
+	ldir
+
+	; Skip return + CR
+	inc hl
+	inc hl
+	jr loop
+	
+run:
+;	jp 0x1234		; Replace with RET if no entry point
+	ret
+	nop
+	nop
+
+endbyte:
+	defb 13
+data:
diff --git a/data/bin2bac.pl b/data/bin2bac.pl
new file mode 100755
index 0000000..4ef7eef
--- /dev/null
+++ b/data/bin2bac.pl
@@ -0,0 +1,110 @@
+#!/usr/bin/perl
+
+use bytes;
+
+sub genpad($$) {
+    my($left, $final) = @_;
+
+    printf STDERR "Padding %d bytes\n", $$left;
+
+    my $o = ($final ? "\x01" : "\x00") . ("\x00" x $$left);
+    $$left = 252;		# Bytes left in block minus end marker
+
+    return $o;
+}
+
+sub bacstmt($$$) {
+    my($line, $left, $data) = @_;
+    my $l = length($data) + 4;
+    my $d = pack("Cv", $l, $line) . $data . "\x0d";
+
+    printf STDERR "bacstmt: l = %d, left = %d\n", $l, $$left;
+
+    if ($l > $$left) {
+	$d = genpad($left,0).$d;
+    }
+
+    $$left -= $l;
+    return $pad.$d;
+}
+
+sub makebac($$) {
+    my($segdata, $entrypt) = @_;
+
+    # <bacldr.asm code>
+    my $bld1 = "\x2a\x1c\xfe\x11";
+    # 16-bit offset from BOFA to first data line between $bld1 and $bld2
+    my $bld2 = "\x19\x06\x00\x3e\xf6\x86\x30\x0e\x0e\x06";
+    $bld2 .= "\x09\x5e\x23\x56\x23\x4f\xed\xb0\x23\x23\x18\xed";
+    # C3 = JP, 00C9 is the address for END in all ABC80 BASIC interpreters
+    $bld2 .= pack("Cv", 0xc3, defined($entrypt) ? $entrypt : 0x00c9);
+
+    # +2 for the offset, +2 for the final 0xbb + CR
+    my $bldlen = length($bld1) + length($bld2) + 2 + 2;
+    print STDERR "bldlen = ", $bldlen, "\n";
+
+    my $q  = "\x82";		# Output (program start marker)
+    my $left = 251;		# Bytes left in block
+    my $r = 0;			# Last emitted line number
+
+    # 1 E%=PEEK(65054%)+SWAP%(PEEK(65055%))	[EOFA]
+    $q .= bacstmt(++$r, \$left,
+		  "\x83\xc1\xf1\x45\x37\x80\xc7\x1e\xfe\xce\x36\xc7".
+		  "\x1f\xfe\xce\x36\xce\x34\xf5\xb7");
+    # 2 Z%=CALL(E%-<loader offset>)
+    $q .= bacstmt(++$r, \$left,
+		  "\x83\xc1\xf1\x5a\x37\x80\xc1\xf1\x45\xba\x0d\xd5\xc7".
+		  pack("v",$bldlen)."\xf8\xce\x3a\xb7");
+
+    my $pfxlen = length($q) - 1; # The initial 0x82 isn't stored in RAM
+    my $bld = $bld1 . pack("v", $pfxlen) . $bld2;
+    print STDERR "pfxlen = ", $pfxlen, "\n";
+
+    foreach my $sega ( sort(keys(%{$segdata})) ) {
+	my $addr = $sega;
+	my $data = ${$segdata}{$sega};
+
+	my $i = 0;
+	my $dl = length($data);
+	while ($i < $dl) {
+	    my $l = $dl - $i;
+
+	    printf STDERR "left = %d, l = %d\n", $left, $dl;
+
+	    # 9 = 3 byte BAC header + 6 byte overhead + CR
+	    $q .= genpad(\$left,0) if ($left <= 10);
+	    $l = $left-10 if ($l > $left-10);
+
+	    printf STDERR "Line %d address %04X, %d/%X bytes\n",
+	    $r+1, $addr, $l, $l;
+
+	    # String expression + address + data + return
+	    $q .= bacstmt(++$r, \$left, "\xcb\"".pack("C", $l+2).
+			  pack("v",$addr).substr($data,$i,$l)."\xbb");
+
+	    $i += $l;
+	    $addr += $l;
+	}
+    }
+
+    # Terminal END statement
+    $q .= bacstmt(++$r, \$left, "\x86\x8a"); # END
+
+    # Loader code (string expression)
+    $q .= bacstmt(++$r, \$left, "\xcb\"".pack("C",length($bld)).$bld."\xbb");
+    $q .= genpad(\$left,1);
+
+    return $q;
+}
+
+($file, $org, $entry) = @ARGV;
+
+$org = oct $org if ( $org =~ /^0/ );
+
+open(FILE, '<:raw', $file) or die "$0: $file: $!\n";
+$l = read(FILE, $dd, 65536);
+close(FILE);
+
+$segs{$org} = $dd;
+
+print makebac(\%segs, $entry);