1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/Makefile	Wed Feb 21 12:00:13 2018 +0200
     1.3 @@ -0,0 +1,35 @@
     1.4 +asrc = $(wildcard src/*.s)
     1.5 +obj = $(asrc:.s=.o)
     1.6 +
     1.7 +name = test
     1.8 +elf = $(name).elf
     1.9 +bin = $(name).bin
    1.10 +adf = $(name).adf
    1.11 +bootblock = boot.bin
    1.12 +
    1.13 +tool_prefix = m68k-linux-gnu-
    1.14 +
    1.15 +CC = $(tool_prefix)gcc
    1.16 +AS = $(tool_prefix)as
    1.17 +LD = $(tool_prefix)ld
    1.18 +OBJCOPY = $(tool_prefix)objcopy
    1.19 +
    1.20 +ASFLAGS = -m68000
    1.21 +LDFLAGS = -T amiga.ld -print-gc-sections \
    1.22 +		  -L/usr/lib/gcc-cross/m68k-linux-gnu/6 -lgcc
    1.23 +
    1.24 +$(adf): $(bin) $(bootblock)
    1.25 +	tools/mk_adf.py $(bootblock) $(bin) $@
    1.26 +
    1.27 +$(bin): $(elf)
    1.28 +	$(OBJCOPY) -O binary $< $@
    1.29 +
    1.30 +$(elf): $(obj)
    1.31 +	$(LD) -o $@ $(obj) -Map link.map $(LDFLAGS)
    1.32 +
    1.33 +$(bootblock): src/boot/boot.o
    1.34 +	$(OBJCOPY) -O binary $< $@
    1.35 +
    1.36 +.PHONY: clean
    1.37 +clean:
    1.38 +	rm -f $(obj) $(bin) $(elf)

     2.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     2.2 +++ b/amiga.ld	Wed Feb 21 12:00:13 2018 +0200
     2.3 @@ -0,0 +1,27 @@
     2.4 +OUTPUT_ARCH(m68k)
     2.5 +
     2.6 +MEMORY
     2.7 +{
     2.8 +	chipram : ORIGIN = 0, LENGTH = 0x80000
     2.9 +}
    2.10 +
    2.11 +PROVIDE (_stacktop = 0x80000);
    2.12 +
    2.13 +SECTIONS {
    2.14 +	/* bootblock will load us at 100h, after the interrupt vectors */
    2.15 +	. = 0x100;
    2.16 +
    2.17 +	.text : { * (.text); } >chipram
    2.18 +	.rodata : { * (.rodata); } >chipram
    2.19 +	.data : { * (.data); } >chipram
    2.20 +
    2.21 +	.bss ALIGN(4): {
    2.22 +		_bss_start = .;
    2.23 +		* (.bss);
    2.24 +		. = ALIGN(4);
    2.25 +		_bss_end = .;
    2.26 +	} >chipram
    2.27 +	_bss_size = SIZEOF(.bss);
    2.28 +
    2.29 +	.dummy ALIGN(4): { LONG(42); } >chipram
    2.30 +}

     3.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     3.2 +++ b/src/boot/boot.s	Wed Feb 21 12:00:13 2018 +0200
     3.3 @@ -0,0 +1,24 @@
     3.4 +| vi:filetype=gas68k:
     3.5 +
     3.6 +	.equ CMD_READ, 2
     3.7 +
     3.8 +	.equ EXEC_DO_IO, -0x1c8
     3.9 +
    3.10 +| starting with trackdisk device I/O request pointer in a1
    3.11 +| load the program at 0x100 and return with that value in a0
    3.12 +| program length is patched by mk_adf at start - 4
    3.13 +start:
    3.14 +	move.l #0x100, 0x28(%a1)	| I/O data pointer
    3.15 +	move.l start - 4, 0x24(%a1)	| I/O length (1 sector for now)
    3.16 +	move.l #512, 0x2c(%a1)		| I/O offset (skip first sector)
    3.17 +	move.w #CMD_READ, 0x1c(%a1)	| I/O command
    3.18 +	move.l %a1, -(%sp)
    3.19 +	jsr EXEC_DO_IO(%a6)
    3.20 +	move.l (%sp)+, %a1
    3.21 +	move.b 0x1f(%a1), %d0
    3.22 +
    3.23 +	move.l #0x100, %a0
    3.24 +	rts
    3.25 +
    3.26 +	.ascii "bootblock_end"
    3.27 +	.align 4

     4.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     4.2 +++ b/src/startup.s	Wed Feb 21 12:00:13 2018 +0200
     4.3 @@ -0,0 +1,27 @@
     4.4 +| vi:filetype=gas68k:
     4.5 +	.text
     4.6 +
     4.7 +	.equ REG_COL0, 0xdff180
     4.8 +
     4.9 +	.global start
    4.10 +	.global halt_cpu
    4.11 +
    4.12 +start:
    4.13 +	| zero the .bss section
    4.14 +	move.l #_bss_start, %a0
    4.15 +	move.l #_bss_end, %a1
    4.16 +	cmp.l %a0, %a1
    4.17 +	beq.s 1f	| skip zeroing if the section is empty
    4.18 +0:	clr.l (%a0)+
    4.19 +	cmp.l %a0, %a1
    4.20 +	bne.s 0b
    4.21 +1:
    4.22 +	| setup the stack
    4.23 +	move.l #_stacktop, %sp
    4.24 +
    4.25 +	| test output
    4.26 +	move.w #0xf0f, REG_COL0
    4.27 +0:	bra.b 0b	| infloop
    4.28 +
    4.29 +halt_cpu:
    4.30 +	stop #0x2700

     5.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     5.2 +++ b/tools/mk_adf.py	Wed Feb 21 12:00:13 2018 +0200
     5.3 @@ -0,0 +1,56 @@
     5.4 +#!/usr/bin/python
     5.5 +# mk_adf.py <bootblock> <payload> <output_adf>
     5.6 +#
     5.7 +# Stuff a given bootblock and payload into an output ADF image.
     5.8 +# 
     5.9 +# Written & released by Keir Fraser <keir.xen@gmail.com>
    5.10 +# 
    5.11 +# This is free and unencumbered software released into the public domain.
    5.12 +# See the file COPYING for more details, or visit <http://unlicense.org>.
    5.13 +
    5.14 +import struct, sys
    5.15 +
    5.16 +# Amiga bootblock checksum
    5.17 +def checksum(bb, sum=0):
    5.18 +    while len(bb):
    5.19 +        x, bb = struct.unpack(">L",bb[:4]), bb[4:]
    5.20 +        sum += x[0]
    5.21 +        if sum >= (1<<32):
    5.22 +            sum -= (1<<32)-1
    5.23 +    return sum
    5.24 +
    5.25 +def main(argv):
    5.26 +    bb_f = open(argv[1], "rb")
    5.27 +    pl_f = open(argv[2], "rb")
    5.28 +    out_f = open(argv[3], "wb")
    5.29 +    bb_dat = bb_f.read()
    5.30 +    pl_dat = pl_f.read()
    5.31 +
    5.32 +    # Construct bootblock header. We will splice in the checksum later.
    5.33 +    header = struct.pack(">ccccLLLL",
    5.34 +                         'D', 'O', 'S', '\0',         # Bootblock signature
    5.35 +                         0,                           # Checksum (placeholder)
    5.36 +                         880,                         # Root block
    5.37 +                         0x60060000,                  # BRA.B +6
    5.38 +                         (len(pl_dat) + 511) & ~511)  # Payload length, padded
    5.39 +                         
    5.40 +    
    5.41 +    # Compute checksum over header, bootblock, and first 512 bytes of payload.
    5.42 +    sum = checksum(pl_dat[:512], checksum(bb_dat, checksum(header)))
    5.43 +    sum ^= 0xFFFFFFFF
    5.44 +    # Splice the computed checksum into the header
    5.45 +    header = header[:4] + struct.pack(">L", sum) + header[8:]
    5.46 +    # Write out the header and bootblock code
    5.47 +    out_f.write(header)
    5.48 +    out_f.write(bb_dat)
    5.49 +    # Pad bootblock to 512 bytes
    5.50 +    for x in xrange((512-len(bb_dat)-len(header))/4):
    5.51 +        out_f.write(struct.pack(">L", 0))
    5.52 +    # Write the payload from sector 1 onwards
    5.53 +    out_f.write(pl_dat)
    5.54 +    # Pad the ADF image to 880kB
    5.55 +    for x in xrange((901120-len(pl_dat)-512)/4):
    5.56 +        out_f.write(struct.pack(">L", 0))
    5.57 +        
    5.58 +if __name__ == "__main__":
    5.59 +    main(sys.argv)