font dumping tool

assets/disk0/home/dumpfont.js

@@ -0,0 +1,38 @@
+if (!_TVDOS) {
+    println("This program can only run on TVDOS")
+    return 1
+}
+if (!exec_args[1]) {
+    println("Usage: dumpfont <rom_prefix>")
+    println("       e.g. if rom_prefix is 'home/myfont', the output files will be 'home/myfont_low.chr' and 'home/myfont_high.chr'")
+    return 1
+}
+
+let lowfilename = exec_args[1] + "_low.chr"
+let highfilename = exec_args[1] + "_high.chr"
+
+let workarea = sys.malloc(1920)
+
+// dump low rom
+sys.poke(-1299460, 16)
+for (let i = 0; i < 1920; i++) {
+    let byte = sys.peek(-1300607 - i)
+    sys.poke(workarea + i, byte)
+}
+
+filesystem.open("A", lowfilename, "W")
+dma.ramToCom(workarea, filesystem._toPorts("A")[0], 1920)
+println("Wrote CHR rom " + lowfilename)
+
+// dump high rom
+sys.poke(-1299460, 17)
+for (let i = 0; i < 1920; i++) {
+    let byte = sys.peek(-1300607 - i)
+    sys.poke(workarea + i, byte)
+}
+
+filesystem.open("A", highfilename, "W")
+dma.ramToCom(workarea, filesystem._toPorts("A")[0], 1920)
+println("Wrote CHR rom " + highfilename)
+
+sys.free(workarea)