Merge development so far - initial success

There is a somewhat working system without disk write, and incorrect disk parameters, but can do `DIR` and load/run `MBASIC.COM` for example.
lgblgblgb · Oct 4, 2024 · cbe2e3b · cbe2e3b
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diff --git a/.gitattributes b/.gitattributes
@@ -0,0 +1,13 @@
+*.c linguist-language=C
+*.h linguist-language=C
+*.cdata linguist-language=C
+*.asm linguist-language=Assembly
+*.inc linguist-language=Assembly
+*.s linguist-language=Assembly
+*.S linguist-language=Assembly
+*.a65 linguist-language=Assembly
+*.i65 linguist-language=Assembly
+Makefile.* linguist-language=Makefile
+Makefile linguist-language=Makefile
+*.mk linguist-language=Makefile
+*.py linguist-language=Python
diff --git a/.gitignore b/.gitignore
@@ -0,0 +1,13 @@
+/*.o
+/*.map
+/*.sym
+/*.pyc
+/*.pyo
+/*.d81
+/*.prg
+/*.lst
+/uart.sock
+/dump.mem
+/serial.raw
+/runme.bin
+/cpm.dsk
diff --git a/8080/.gitignore b/8080/.gitignore
@@ -0,0 +1,3 @@
+/*.lst
+/*.sym
+/mbasic-real.com
diff --git a/8080/Makefile b/8080/Makefile
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+SJASM		= sjasm
+ALL_DEPENDS	= Makefile
+CPM_UTILS	= cpmver.asm
+BINARIES	= $(CPM_UTILS:.asm=.com)
+
+all: $(BINARIES)
+
+%.com: %.asm $(ALL_DEPENDS)
+	$(SJASM) -s $< $@ || { rm -f $@ $(@:.com=.lst) $(@:.com=.sym) ; false; }
+
+
+clean:
+	$(RM) -f *.sym *.lst $(BINARIES)
+
+
+.PHONY: all clean
diff --git a/Makefile b/Makefile
@@ -0,0 +1,91 @@
+## i8080 CPU emulator and CP/M v2.2 compatible BIOS for MEGA65
+##
+## Copyright (C)2017,2024 LGB (Gábor Lénárt) <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+DISK_IMAGE	= emu.d81
+PRG		= emu.prg
+LD65_CFG	= emu.ld
+PRG_ON_DISK	= emu
+MAP_FILE	= emu.map
+SOURCES		= console.asm cpu.asm loader.asm main.asm shell.asm fontdata.asm disk.asm
+INCLUDES	= $(shell ls *.inc) cpm/bios.inc cpm/cpm22.inc
+OBJECTS		= $(SOURCES:.asm=.o)
+M65_IP		= 192.168.0.65
+ALL_DEPENDS	= Makefile
+
+CA65_OPTS	= -t none
+LD65_OPTS	= -C $(LD65_CFG) -m $(MAP_FILE) -vm
+
+XEMU_M65	= xemu-xmega65
+#XEMU_M65	= /home/lgb/prog_here/xemu-dev/build/bin/xmega65.native
+
+ETHERLOAD	= mega65-etherload
+C1541		= c1541
+CA65		= ca65
+LD65		= ld65
+RM		= rm
+GUNZIP		= gunzip
+
+
+all: $(DISK_IMAGE)
+
+cpu_tables.inc: cpu_gen_tables.py
+	rm -f cpu_tables.inc
+	./cpu_gen_tables.py > $@
+
+cpm/bios.inc cpm/cpm22.inc cpm/bios.bin cpm/cpm22.bin:
+	$(MAKE) -C cpm
+
+%.o: %.asm $(ALL_DEPENDS) $(INCLUDES)
+	$(CA65) $(CA65_OPTS) --listing $(<:.asm=.lst) -o $@ $<
+
+main.o: 8080/*.com 8080/mbasic-real.com
+
+$(PRG): $(OBJECTS) $(LD65_CFG) $(ALL_DEPENDS)
+	$(LD65) $(LD65_OPTS) -o $@ $(OBJECTS)
+
+cpm.dsk: diskdefs Makefile
+	rm -f $@
+	mkfs.cpm -f mega65 $@
+	cpmcp -f mega65 $@ dist/cpm-apps/* 0:
+	cpmls -f mega65 -D $@
+
+runme.bin: runme.asm
+	cl65 -t none -o $@ $<
+
+$(DISK_IMAGE): $(PRG) runme.bin cpm.dsk $(ALL_DEPENDS)
+	$(RM) -f $@
+	echo "format lgb-test,00 d81 $@\nwrite runme.bin runme\nwrite $(PRG) $(PRG_ON_DISK)\nwrite cpm.dsk\ndir\n" | $(C1541)
+
+ethertest: $(PRG) $(ALL_DEPENDS)
+	$(ETHERLOAD) $(M65_IP) $(PRG)
+
+xemu:	$(PRG) $(DISK_IMAGE)
+	$(XEMU_M65) -hyperserialfile serial.raw -fastboot -8 $(DISK_IMAGE) -initattic cpm.dsk -prg $(PRG)
+
+dist:	$(DISK_IMAGE)
+	cp emu.d81 dist/bin/mega65.d81
+
+clean:
+	$(RM) -f $(PRG) *.o *.lst $(DISK_IMAGE) $(MAP_FILE) runme.bin cpm.dsk
+	$(MAKE) -C cpm clean
+
+distclean:
+	$(MAKE) clean
+	$(RM) -f 8080/*.com uart.sock dump.mem serial.raw
+
+.PHONY: all clean distclean xemu ethertest dist
diff --git a/README.md b/README.md
@@ -1,5 +1,68 @@
-# TODO
+# MEGA/80: i8080 emulator and CPM BIOS for MEGA65
 
-Trying to renew my old project from 2017 to be able to run CP/M on MEGA65
-with i8080 (for now, later: Z80) emulated in software.
+I'm trying to renew my old project from 2017 to be able to run CP/M on MEGA65
+with i8080 (for now, later: Z80) emulated in software equipped with a custom
+CBIOS for the task. The 65816 CPU also seems to be a possible target to port
+future Z80 emulation (I wouldn't do for the current i8080 since I will rewrite
+the emulator anyway).
+
+## Running CP/M
+
+For now, i8080 CPU (which is the original CPU for CP/M, not the Z80) is emulated.
+A custom CP/M v2.2 is provided dispatching the work to the native 65xx implementation
+via HALT opcodes. For now, original DR's CPM (BDOS and CCP) v2.2 is used.
+
+## Download
+
+Have a look in directory `dist/bin` for a D81 disk image file (`mega65.d81`) for MEGA65.
+
+## Limitations / problems / plans
+
+* Current code base is chaotic since major parts of it was written by me in 2017 and I only
+  try to revive some unfinished old work of mine here
+* So far only i8080 emulation, not Z80: newer CP/M programs written for Z80 won't work
+* Even i8080 is not emulated perfectly, no half-carry flag and no DAA and for sure can be many bugs
+* Original DR BDOS and CCP. There are open souce GNU/GPL replacements but requires Z80
+* In nutshell, I would guess I'll go for Z80 emulation later and don't plan to fix i8080 emulation bugs too much
+* No real disk access, CP/M disk image is copied to MEGA65 Attic RAM on startup and all changes later will be lost
+* Only "dumb" terminal emulation, `CR`, `LF` and `BS` is interpreted. For more advanced CP/M programs, some terminal emulation should be done
+* Need some tool which at least makes possible to easily import files into CP/M from MEGA65 SD card or such (at runtime)
+* Porting to other systems: 65816 CPU seems to be a viable option for porting, and machines using that CPU and having enough memory:
+    * Commodore 64 with SuperCPU
+    * Commander X16 **if** CPU is 65816 and it can access RAM in higher bankes freely
+    * Apple IIgs? Unfortunately I don't know too much about Apple computers, but could be a fun ...
+* Porting for non-65xx CPU based platforms: certainly it's not impossible but then you need to rewrite everything,
+  as it's an assembly project.
+* Integrated on-the-fly memory monitor and things like that
+* No, I don't plan CP/M v3. The problem: it requires extensive bank switching and other difficulties,
+  since I'm emulating i8080 (later hopefully a Z80) emulating bank switching would be impossible or very slow
+
+## Building
+
+Tools needed to build:
+
+### CC65
+
+Various tools (ca65, ld65, cl65) from the CC65 suite to assemble 65xx assembly sources:
+
+Only tested with V2.18 (as of I am writing this), so any older version can cause
+problems. Currently the C compiler part (cc65) is not used though.
+
+### SjASMPlus
+
+SjASMPlus Z80 Cross-Assembler to assemble i8080 / Z80 assembly sources: https://github.com/z00m128/sjasmplus
+
+Only tested with version v1.20.3 (as of I am writing this), so any older version
+can cause problems, like certain ASSERT features was introduced in v1.18.1 but there
+can be other problems as well.
+
+### Standard UNIX stuff, like sed, make ...
+
+### Python 3
+
+### c1541
+
+### cpmtools
+
+### wget
 
diff --git a/README.md.OLD b/README.md.OLD
@@ -0,0 +1,67 @@
+# i8080 (software) emulator and CP/M for the MEGA65
+
+Foreword: this project of mine is from 2017! Now I'm trying to catching up
+again.
+
+Goal: to try to provide a CP/M for the MEGA65 with software emulation of the
+i8080 CPU initially, Z80 later and writing a CP/M v2.2 compatible BIOS so
+the original DR BDOS (or some replacement like ZSDOS - though it will require
+a Z80 emulation) can work.
+
+
+However CP/M application runs with the 8080 emulation using some "trap opcode"
+to dispatch BIOS and BDOS call into native mode. File system based (only file
+level, not disk block!) would be translated to MEGA65 hypervisor DOS calls,
+thus the native SD-Card formatted for FAT32 would be usable by orginal CP/M
+applications as well.
+
+This project contains the following major "tricks" (not so much tricks, and
+maybe not as good as it can be, but still some ideas and examples on M65):
+
+* C65 basic-stub loader (so you must start the program in C65 mode! Not C64!!)
+* Usage of MAP opcode, C65/M65 memory model, etc
+* M65 speed control
+* "32 bit linear addressing" opcodes
+* M65 direct character "WOM" (write-only memory) access
+* Usage of some 65CE02 opcodes (but some of them exists on 65C02 or 65816 as
+  well, though the opcode bytes can be even different!), like TRB, TSB,
+  BBRx, BBSx, SMBx, RMBx, Z-reg pased ops, INW, 16 bit branches, and such.
+* As a bonus: one time it already helped to find a bug in Xemu/MEGA65 with
+  rarely used CPU feature (ADC opcode with 32 bit addressing)
+
+## Compile
+
+As usual, you need quite decent CA65 (from cc65) assembler with "4510" CPU
+support (currently, maybe only git version is good enough for this?). You
+also need an average UNIX-or UNIX like (Linux, OSX, even maybe Windows with
+cygwin, or some Linux-box solution) development environment, with GNU make,
+wget, and other standard utilities. You also need Python to be installed.
+
+You can say 'make' to compile everything, or 'make test' to test the result
+in Xemu MEGA65 emulation (you need only the binary to be installed somewhere
+in your search path, it will fetch things for you, if needed with wget).
+
+## Current problems and limitations
+
+* i8080 emulation is farily complete as the emulated opcodes, though there
+  can be huge amount of bugs, not so much tested. Also now only "DAA"
+  is not emulated, since the half-carry flag is not emulated at all, it's
+  really a pain in the ass to do :(
+* Also, some i8080 features are not implemented, like the "half-carry" flag,
+  which may cause problems (surly with DAA but there can be other cases too)
+* "Terminal" handling is a big mess of unoptimized quickly written code,
+  this is not the major point for now
+* i8080 emulation has problems with cases when operands/etc would cross the
+  64K boundary. Surely it can be handled, but emulation would be slower to
+  do this. I think, this case shouldn't be used anyway by a regular CP/M
+  program too much ...
+* Of course there can be TONS of bogs on opcode emulations ...
+* Usage of M65 character-WOM is neat idea to demonstrate the technique, but
+  it has a serious problem: after "exiting", screen will be messed up, because
+  my i8080 emulator installs ASCII-compatible character generator layout for
+  more comfortable usage of I/O routines.
+* Currently not so much BDOS and BIOS calls work, what would be the major
+  intent here, besides the 8080 emulation.
+* "Console" emulation if fairly incomplete, screen scrolling should be done
+  with DMA, control codes should be implemented, there is no keyboard yet
+  at all (only output), etc ...
diff --git a/boot/Makefile b/boot/Makefile
@@ -0,0 +1,11 @@
+CPMSYS = ../emu.prg
+MAXBLOCKS = 100
+
+boot: boot.asm $(CPMSYS) config_maker.py Makefile
+	rm -f boot.inc
+	python config_maker.py $(CPMSYS) $(MAXBLOCKS) > boot.inc
+	cl65 -t none --cpu 4510 --config boot.ld -o boot boot.asm
+
+clean:
+	rm -f boot boot.inc *.o
+
diff --git a/boot/README b/boot/README
@@ -0,0 +1,2 @@
+https://codebase64.org/doku.php?id=base:reading_a_sector_from_disk
+
diff --git a/boot/boot.asm b/boot/boot.asm
@@ -0,0 +1,26 @@
+; Boot code, needs "BOOT SYS" command from BASIC65
+
+.INCLUDE "boot.inc"		; file created by config_maker.py
+
+.CODE
+
+	JMP	boot		; we want to jump over the disk identifier, ALSO "JMP" ($4C opc) is a must for ROM to be recognized!
+
+.BYTE "MC80"			; disk indentifier (at offset 3, we are now) for MEGA65 CP/M
+
+boot:
+
+	RTS
+
+	JMP	LOAD_ADDR	; pass control to the loaded program
+
+
+
+
+
+.SEGMENT	"PAYLOAD"
+.INCBIN		LOAD_BIN_FN, LOAD_OFFSET
+.IF		PADDING <> 0
+	.RES	PADDING, $00
+.ENDIF
+
diff --git a/boot/boot.ld b/boot/boot.ld
@@ -0,0 +1,15 @@
+FEATURES {
+	STARTADDRESS:	default = $400;
+}
+MEMORY {
+	ZP:		file = "", define = yes, start = $0002, size = $00F0;
+#        RAM:		file = %O, start = %S, size = $C000 - %S, define = yes;
+	BOOTSECTOR:	file = %O, start = $400, size = $200, define = yes, fill = yes;
+	CPMSYS:		file = %O, start = $2001 - 2, size = $C000 - $2001 - 2;
+}
+SEGMENTS {
+	ZEROPAGE:	load = ZP, type = zp;
+	CODE:		load = BOOTSECTOR;
+	PAYLOAD:	load = CPMSYS, define = yes;
+	BSS:		load = CPMSYS, type = BSS;
+}
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		https://codebase64.org/doku.php?id=base:reading_a_sector_from_disk