This guide lets to create a bootable SCSI 1.3 ROM just using Capitoline.<\/p>\n\n\n\n
Cap does not contain any C=\/Amiga code, so will need need<\/p>\n\n\n\n
Note, if you haven’t extracted the library from the ROM, but you have the a 3.1 ROM, you can add it directly from the ROM without extracting;<\/p>\n\n\n\n
i.e. instead of;<\/p>\n\n\n\n
add Components\/os-source\/v40\/0x75094a7b.scsidisk_40.12_(21.12.93)<\/strong><\/pre>\n\n\n\nYou can;<\/p>\n\n\n\n
add \"\/location\/of\/3.1 Kickstart\" scsi.device\ne.g. add \"ROMs\/TOSEC.Firmware\/Kickstart v3.1 r40.068 (1993-12)(Commodore)(A1200)[!].rom\" scsi.device<\/strong><\/pre>\n\n\n\nPart 1 – Create the “lower” 0xF8000 ROM for SCSI<\/h2>\n\n\n\n
Create an empty ROM with a 0xF80000 ROMBASE, add the 0xFC0000 ROMHEADER (or it won’t boot)<\/p>\n\n\n\n
Add the scsidisk library (in this case from the A1200 40.68 KS3.1)<\/p>\n\n\n\n
Add the extra code which creates a “boot node” to allow the disk to boot<\/p>\n\n\n\n
newrom 256k 255 \nrombase 0xf80000\u00a0\nadd Components\/BinaryChunks\/ROMHeader_FC.bin\u00a0\nadd Components\/os-source\/v40\/0x75094a7b.scsidisk_40.12_(21.12.93)\u00a0\nadd Components\/BinaryChunks\/add_boot_node.bin<\/strong><\/pre>\n\n\n\nPatch the SCSI library so that it calls the new code – there’s two locations to patch.<\/p>\n\n\n\n
findopcode $0x75094a7b.scsidisk_40.12_(21.12.93) \"JSR FCD6(A6)\"\nalias OPCODE $add_boot_node.bin.(START) \nalias OPCODE subtract $FIND \nalias OPCODE subtract 2 \nalias OPCODE add 0x61000000 \npatch $FIND $OPCODE \nfindopcode $0x75094a7b.scsidisk_40.12_(21.12.93) \"JSR FFDC(A6)\" \nalias OPCODE $add_boot_node.bin.(START) \nalias OPCODE subtract $FIND \nalias OPCODE add 26 \nalias OPCODE add 0x61000000 \npatch $FIND $OPCODE<\/strong><\/pre>\n\n\n\nNext add the code to initialise Gayle (assuming you have a Gayle or emulate Gayle)<\/p>\n\n\n\n
add Components\/BinaryChunks\/init_gayle.bin<\/strong><\/pre>\n\n\n\nPatch the scsi.library INIT (ROMTAG.INIT) call to jump into the new code<\/p>\n\n\n\n
alias SCSIINIT romdata $0x75094a7b.scsidisk_40.12_(21.12.93).(ROMTAG.INIT) 4\nalias GAYLE $init_gayle.bin.(START) \nalias GAYLE add $ROMBASE \npatch $0x75094a7b.scsidisk_40.12_(21.12.93).(ROMTAG.INIT) $GAYLE<\/strong><\/pre>\n\n\n\nPatch the Gayle init code to jump to the original address of the scsi.library INIT which we saved in SCSIINIT<\/p>\n\n\n\n
alias GAYLE $init_gayle.bin.(END) \nalias GAYLE subtract 4 \npatch $GAYLE $SCSIINIT<\/strong><\/pre>\n\n\n\nFinally, add the standard ROM components, and checksum it – then we’re all done for $F80000<\/p>\n\n\n\n
add checksum\nadd size\nadd vectors\nchecksum<\/strong><\/pre>\n\n\n\nPart 2 – Patch the original 1.3 ROM the “upper” $FC0000 ROM<\/h2>\n\n\n\n
Next we need to load the original KS1.3 and patch its library scan table to look at $F80000-$FC0000 as it normally doesn’t – luckily, for 1.3 it seems to scan $FC0000-$10000000 twice, so we can overwrite the second one (makes the patch simple), analyserom is used to find exec, in case you don’t have the full kickstart definition file, don’t forget to checksum.<\/p>\n\n\n\n
loadrom \"ROMs\/TOSEC.Firmware\/Kickstart v1.3 r34.005 (1987-12)(Commodore)(A500-A1000-A2000-CDTV)[!].rom\nanalyserom\nfind $exec.library 0x00FC00000100000000FC00000100000000F0000000F80000FFFFFFFF\npatch $FIND 0x00FC00000100000000F8000000FC000000F0000000F80000FFFFFFFF\nchecksum<\/strong><\/pre>\n\n\n\nPart 3 – Save your work!<\/h2>\n\n\n\n
Join the two ROMs together and save the file, you might want to use “saveprofile test_ks1.3scsi.rom byteswap” if you’re buring a real ROM<\/p>\n\n\n\n
romprofile 0 1\nsaveprofile test_ks1.3scsi.rom<\/strong><\/pre>\n\n\n\nAcknowledgements<\/h2>\n\n\n\n
I didn’t develop the code that creates the boot node, I found it in the Commodore docs when it talked about manually creating a boot node, this and the code for checking the version of expansion.library was in the GetSCSI11 code developed by Torbj\u00f6rn Andersson which you can find Here<\/a> on Aminet.<\/p>\n\n\n\n