Initial (#2)

* Initial commit

* Remove project files

* Tidy up

* Corrected two bugs when flushing buffers

* Corrections

* Clean up

* Correct capitalisation

* Change target cpu to 68000

* Initial readme (#1)

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Added image boot image

* Added boot instruction and images

* Added contributions.

* Update README.md

.gitignore

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+/obj/
+/.project

Makefile

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+SUBDIRS := boot bios cpmfs
+
+all: $(SUBDIRS)
+
+$(SUBDIRS):
+	$(MAKE) -C $@
+
+.PHONY: all $(SUBDIRS)

README.md

@@ -1 +1,90 @@
-# cpm-68k
+# CP/M 68K for the S100 68000/68010 Board
+
+This project provides:
+* Boot loader/monitor
+* CP/M 68K BIOS
+* CP/M file system images
+
+This code assumes, and has been tested with, the following hardware:
+* [68000/68010 Board](http://www.s100computers.com/My%20System%20Pages/68000%20Board/68K%20CPU%20Board.htm)
+* [Propeller Console IO Board](http://www.s100computers.com/My%20System%20Pages/Console%20IO%20Board/Console%20IO%20Board.htm)
+* [16MB Static RAM Board](http://www.s100computers.com/My%20System%20Pages/16MG%20RAM%20Board/16MG%20RAM%20Board.htm)
+* [IDE/CF Board](http://www.s100computers.com/My%20System%20Pages/IDE%20Board/My%20IDE%20Card.htm)
+
+# Release
+
+The release contains the following files:
+* boot.srec - This is the boot loader / monitor in SRecord format and  must be burnt into the board's EPROMS,normal even/odd configuration.
+* bios.srec - This is the bios in SRecord format.
+* boot400.sr - This is the patched cpm400.sr and bios.srec concatenated into a single SRecord file
+* disk1.img Single partition image using the 4mb-hd format containing boot400.sr and the contents of DISK1 of the CP/M 68K V1.3 binary distribution
+* disk10.img Ten partition image using the 4mb-hd format, paritions 0 to 8 contain DISK1 - DISK9 of the CP/M 68K v1.3 binary distribution.  boot400.sr is in partition 0, partition 9 is empty.
+* diskAll.img Ten partition image using the 4mb-hd format, paritions 0 contains all files from DISK1 - DISK9 of the CP/M 68K v1.3 binary distribution plus boot400.sr.  Partitions 1 - 9 are empty.
+
+# Executing
+
+1. Burn the boot.srec file into the boards EPROMS.  Copy one of the file system images to a CF card using your preferred tool, dd, balenaEtcher, etc.
+1. Boot the 68000 into the boot loader/monitor.  Type `help<ENTER>` for a list of available commands.
+1. Select the appropriate disk drive, a or b.
+1. Type `boot boot400.sr<ENTER>` and the loader will start reading the file into memory.
+1. When loading is complete, you will be prompted to continue, enter `y`.
+
+You should now see the CP/M `A>` prompt.
+
+![boot](cpm_boot_b.png)
+
+# Building
+
+Requires git, make, gnu 68000 cross tools, cpmtools to be installed.
+
+Alternatively, use the following docker image which provides all the necessary tools:
+
+  `docker run -it --rm --name 68k-tools -v {my project directory}:/opt/work dwildie/68k-tools:0.0.1 bash`
+
+The [Dockerfile](https://github.com/dwildie/68k-tools/blob/master/docker/Dockerfile) documents the required tool installation.
+
+Clone the repository: `git clone https://github.com/dwildie/cpm-68k.git`
+
+To build:  In the top level directory, type `make`
+
+## Boot loader/monitor
+The Boot loader/monitor is build for the standard memory configuration:
++ 32KB RAM at 0xFD8000
++ 32KB ROM at 0xFD0000
+
+For a different memory configuration modify the MEMORY section in the `boot.rom.lnk` file.
+
+Once built, the target directory will contain `boot.srec` which should be burnt to the EPROMs, normal even/odd config.
+
+## CP/M 68K BIOS
+The BIOS is configured for a full populated 16MB static RAM board.  For a different memory configuration, modify the MEMORY section in the `bios.lnk` file.  The CP/M memory region table's entry is derived from the `bios.lnk` configuration so it must reflect the target hardware.
+
+This BIOS delegates all console and disk IO to the boot loader/monitor.  Therefore, it will not function with another monitor.
+
+The BIOS has a tuneable LRU disk buffer.  The tuning parameters are in `buffer.i`:
++ `BUFFER_COUNT` - The number of available buffers.  Buffers are reused based on a LRU algorithm.
++ `BUFFER_SECTORS` - The size of each buffer in HDD sectors (512 bytes).  The maximum size is 32 sectors, ie. 16KB per buffer.
+
+The current configuration is:
++ `BUFFER_COUNT = 4`
++ `BUFFER_SECTORS = 8`
+
+The BIOS is configured to support a maximum of 10 drives mapped to a single multi-partitioned disk image.  This can be increased by modifying the `DISK_COUNT` value in `bios.i` and allocating additional Disk Parameter Headers in `main.s`.
+
+The BIOS is configured to work with the CPM400.SR system from DISK9 of the [CP/M 68K V1.3 distribution disks](http://cpm.z80.de/download/68kv1_3.zip).  The BIOS `_init` entry point has been moved from the original 0x6000 to 0x6200.  This shifts the BIOS out of the CPM400.SR BSS segment.  CPM400.SR is patched to suit.
+
+Once built, the target directory will contain `bios.srec`.
+
+## CP/M file system images
+Each of the file system images contain the boot400.sr file in the first partition.  This file:
++ Contains the patched cpm400.sr and the bios.sr
++ Is the file that must be loaded and executed to start CP/M
+
+
+Three file system image are built:
++ disk1.img Single partition image using the 4mb-hd format containing boot400.sr and the contents of DISK1 of the CP/M 68K V1.3 binary distribution
++ disk10.img Ten partition image using the 4mb-hd format, paritions 0 to 8 contain DISK1 - DISK9 of the CP/M 68K v1.3 binary distribution.  boot400.sr is in partition 0, partition 9 is empty.
++ diskAll.img Ten partition image using the 4mb-hd format, paritions 0 contains all files from DISK1 - DISK9 of the CP/M 68K v1.3 binary distribution plus boot400.sr.  Partitions 1 - 9 are empty.
+
+# Contributions
+The IDE code used in the boot loader/monitor was originally written by John Monahan who also designed the S-100 cards being used.  Thank you John.

bios/.gitignore

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+/obj/
+/target/

bios/Makefile

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+AS       = m68k-elf-as
+ASFLAGS += -m68000
+ASFLAGS += -alms
+
+CC       = m68k-elf-gcc
+CCFLAGS += -Wall
+CCFLAGS += -m68000
+#CCFLAGS += -ggdb
+CCFLAGS += -nostdlib
+CCFLAGS += -nodefaultlibs
+
+LD       = m68k-elf-ld
+
+all: target/bios.srec 
+
+%.s:	%.c
+	$(CC) $(CCFLAGS) -S $<
+
+# --------------------------------------------------------------------------------
+# M68K CPM Bios
+# --------------------------------------------------------------------------------
+obj/%.o: %.s
+	$(AS) $(ASFLAGS) -a=$(@:.o=.lst) -o $@ $<
+
+obj/bios.srec: obj/main.o obj/buffer.o
+	$(LD) -T bios.lnk obj/main.o obj/buffer.o -Map $(@:.srec=.map) -o $@
+
+target/bios.srec: obj/bios.srec
+	srec_cat $< -fill 0x00 -over $< -header="CP/M-68K S100 Bios" -o $@
+	srec_info $@
+
+clean:
+	rm -rf obj/* target/*
+	mkdir -p obj target
+
+

bios/bios.lnk

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+OUTPUT_FORMAT(srec)
+
+MEMORY
+{
+    ram : ORIGIN = 0x6200, LENGTH = 0x80000
+}
+
+SECTIONS
+{
+  .text : { 
+    __text_start__ = .;
+    *(.text*) 
+    __text_end__ = .;
+  } > ram
+
+  .data : {
+    __data_start__ = .;
+    *(.data*)
+    __data_end__ = .;
+  } > ram
+
+  .bss : { 
+    __bss_start__ = .;
+    *(.bss*) *(COMMON)
+    __bss_end__ = .;
+  } > ram
+
+  __bss_length__ = __bss_end__ - __bss_start__;
+
+  . += 1;
+  . = ALIGN (0x100);
+  __memory_region_start__ = .;
+  __memory_region_end__ = 0x00FCFFFF;
+  __memory_region_length__ = 1 + (__memory_region_end__ - __memory_region_start__);
+
+  /DISCARD/ : {
+    *(.eh_frame);
+    *(.comment);
+  }
+}