CosmOS pre-alpha and launchable application versions of old programs.
This commit is contained in:
Anachronaut
@@ -1,871 +0,0 @@
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; sbfs.asm
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; Reading the SplitBit Filesystem.
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;
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; The other implementation of this format is SplitDisk on the host. Nothing is shared
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; between them but the written specification, so anything that changes here has to change
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; there in the same breath.
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;
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; The disk's buffer is registered as bank 3, and every block read lands there and is then
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; blitted where it is wanted. The CPU never touches the buffer directly, because nothing
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; can: memory a device brings is reachable only through the controller.
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;
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; Written by Anachronaut
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#Program
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; Registers the disk's buffer, reads the superblock, and checks that the disk really is
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; one of ours. Q is zero if the disk is ready to be read.
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sbfsMount:
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INIA 0d3
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OUTA 0xE3
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INIA 0x20
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OUTA 0xE2
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INIA 0x03
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OUTA 0xE8 ; RegisterBank: bank 3 is the disk's buffer.
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SETD.0 SbfsBlock
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RSTA
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STA.0
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INCD.0
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STA.0 ; Block 0, the superblock.
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CALL sbfsReadBlock
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BRQ sbfsMountRead
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RET ; The read failed, and Q says so.
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sbfsMountRead:
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SETD.1 SbfsBuffer
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CALL sbfsBufferOut
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; "SBFS", or this is not a disk of ours. A blank image is all zeroes, so without this
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; an unformatted disk would look like a formatted one with no files on it.
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SETD.0 SbfsBuffer
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SETD.2 SbfsMagic
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INIA 0d4
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SETD.1 SbfsCount
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STA.1
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sbfsMagicLoop:
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CALL sbfsSameByte
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BRQ sbfsMagicSame
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RET ; Q is the difference, which is not zero.
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sbfsMagicSame:
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INCD.0
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INCD.2
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LDA.1
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DECA
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STA.1
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BNA sbfsMagicLoop
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sbfsMagicDone:
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; The version has to be one we understand.
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SETD.0 SbfsBuffer
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DPUP.0 0d04
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LDA.0
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INIB 0d1
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XOR
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BRQ sbfsGeometry
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RET ; A version we do not know.
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sbfsGeometry:
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; Where the directory is and how big it is. The superblock carries both so that disks
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; of different sizes can have different directories without a new format.
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SETD.0 SbfsBuffer
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DPUP.0 0d08
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SETD.1 SbfsDirStart
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CALL sbfsCopyWord
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SETD.0 SbfsBuffer
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DPUP.0 0d10
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SETD.1 SbfsDirBlocks
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CALL sbfsCopyWord
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SETD.0 SbfsBuffer
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DPUP.0 0d06
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SETD.1 SbfsDiskBlocks
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CALL sbfsCopyWord
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RSTA
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RSTB
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CCF
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ADD ; Q is zero: mounted.
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RET
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; Finds a file by name. DP0 points at a name, ending in a zero byte. Q is zero if it was
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; found, and then SbfsFileStart, SbfsFileBlocks and SbfsFileTail describe it.
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sbfsFind:
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SETD.1 SbfsWanted
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CALL sbfsKeepName
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; Start at the first directory block and work through them all.
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SETD.0 SbfsDirStart
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SETD.1 SbfsBlock
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CALL sbfsCopyWord
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SETD.0 SbfsDirBlocks
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DPUP.0 0d01
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LDA.0
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SETD.1 SbfsLeft
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STA.1 ; Only the low byte: a directory of 256 blocks is 2048 files.
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sbfsFindBlock:
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CALL sbfsReadBlock
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BRQ sbfsFindLoaded
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RET ; The read failed.
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sbfsFindLoaded:
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SETD.1 SbfsBuffer
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CALL sbfsBufferOut
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; Eight entries to a block, thirty two bytes each.
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SETD.2 SbfsBuffer
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INIA 0d8
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SETD.1 SbfsCount
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STA.1
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sbfsFindEntry:
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LDA.2
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INIB 0x01
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AND
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BRQ sbfsFindNext ; The in use bit is down, so this entry is free.
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CALL sbfsMatchEntry
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BRQ sbfsFindFound
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sbfsFindNext:
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DPUP.2 0d32
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LDA.1
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DECA
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STA.1
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BNA sbfsFindEntry
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sbfsFindNextBlock:
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SETD.0 SbfsBlock
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CALL sbfsStepWord
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SETD.1 SbfsLeft
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LDA.1
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DECA
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STA.1
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BRA sbfsFindMissing
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BRI sbfsFindBlock
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sbfsFindMissing:
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; Nothing of that name. Q has to be something other than zero to say so.
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RSTA
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INIB 0d1
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CCF
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ADD
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RET
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sbfsFindFound:
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; DP2 is on the entry. Keep it in DP3 while the pieces are taken out of it: DP3 is the
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; pointer a CALL does not put back, so it is the only one that survives a subroutine.
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; Copying it into DP0 has to be done here rather than in a routine of its own, for the
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; same reason: a routine that set DP0 would have the assignment undone by its own RET.
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PSHD.2
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POPD.3
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PSHD.3
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POPD.0
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DPUP.0 0d01
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SETD.1 SbfsFileStart
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CALL sbfsCopyWord
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PSHD.3
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POPD.0
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DPUP.0 0d03
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SETD.1 SbfsFileBlocks
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CALL sbfsCopyWord
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PSHD.3
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POPD.0
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DPUP.0 0d05
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LDA.0
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SETD.1 SbfsFileTail
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STA.1
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RSTA
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RSTB
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CCF
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ADD ; Q is zero: found.
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RET
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; Compares the name in the entry at DP2 with the one kept in SbfsWanted. Q is zero if
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; they are the same. Names are padded with zeroes rather than terminated, so a name that
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; fills the field has no terminator to look for, which is why the count is what stops it.
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sbfsMatchEntry:
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PSHD.2
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POPD.0
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DPUP.0 0d06 ; The name inside the entry.
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SETD.2 SbfsWanted
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INIA 0d22
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SETD.1 SbfsCount
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STA.1
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sbfsMatchLoop:
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CALL sbfsSameByte
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BRQ sbfsMatchSame
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RET ; They differ, and Q is the difference.
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sbfsMatchSame:
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LDA.0
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BRA sbfsMatchYes ; Both ended in the same place.
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INCD.0
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INCD.2
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LDA.1
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DECA
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STA.1
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BNA sbfsMatchLoop ; Twenty two the same is the same name, so falling out is a match.
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sbfsMatchYes:
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RSTA
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RSTB
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CCF
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ADD
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RET
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; Copies the name at DP0 into DP1, twenty two bytes of it, padding with zeroes the way an
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; entry is padded so that the two can be compared as they stand.
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sbfsKeepName:
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INIA 0d22
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SETD.2 SbfsCount
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STA.2
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RSTB ; B stays zero once the name has ended.
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sbfsKeepLoop:
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LDA.0
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BRA sbfsKeepPad
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STA.1
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INCD.0
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BRI sbfsKeepStep
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sbfsKeepPad:
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STB.1
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sbfsKeepStep:
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INCD.1
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LDA.2
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DECA
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STA.2
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BNA sbfsKeepLoop
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sbfsKeepDone:
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RET
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; Reads the file that sbfsFind found into Data Memory at DP1. Q is zero if it worked.
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;
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; Whole blocks are copied whole, including the last one, so the bytes after the end of a
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; file are whatever else was in that block on the disk. SbfsFileTail says where the file
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; actually stops, and it is the caller's business to respect it.
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;
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; A file of more than 255 blocks is not handled here. That is 64K, which is the whole of
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; Data Memory, so it could not be read into it anyway.
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sbfsRead:
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PSHD.1
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POPD.3 ; Where it goes. DP3 survives a CALL, and nothing called here
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; touches it.
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SETD.0 SbfsFileStart
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SETD.1 SbfsBlock
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CALL sbfsCopyWord
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SETD.0 SbfsFileBlocks
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DPUP.0 0d01
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LDA.0
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SETD.1 SbfsLeft
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STA.1
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SETD.0 SbfsFileTail
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LDA.0
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BRA sbfsReadCounted ; No part block on the end.
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SETD.0 SbfsLeft
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LDA.0
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INCA
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STA.0 ; One more block for the tail.
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sbfsReadCounted:
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SETD.0 SbfsLeft
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LDA.0
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BRA sbfsReadDone ; An empty file has nothing to read.
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sbfsReadLoop:
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CALL sbfsReadBlock
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BRQ sbfsReadGot
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RET ; The read failed, and Q says so.
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sbfsReadGot:
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PSHD.3
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POPD.1
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CALL sbfsBufferOut
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; On by a whole block. DPUP carries one byte at a time, so 256 takes two of them.
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DPUP.3 0xFF
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DPUP.3 0x01
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SETD.0 SbfsBlock
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CALL sbfsStepWord
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SETD.0 SbfsLeft
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LDA.0
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DECA
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STA.0
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BNA sbfsReadLoop
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sbfsReadDone:
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RSTA
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RSTB
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CCF
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ADD ; Q is zero: read.
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RET
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; ---- Writing ----
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; Where the first block that can hold a file is: past the superblock and the directory.
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sbfsFirstData:
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SETD.0 SbfsCandidate
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SETD.2 SbfsDirStart
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CALL sbfsSetWord
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SETD.0 SbfsCandidate
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SETD.2 SbfsDirBlocks
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CALL sbfsAddWord
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RET
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; SbfsEntryStart and SbfsEntryEnd describe the file in the entry at DP2. The end is one
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; past the last block it holds, and a file of nothing holds none, so its end is its start.
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sbfsEntryBounds:
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PSHD.2
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POPD.3
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PSHD.3
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POPD.0
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DPUP.0 0d01
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SETD.1 SbfsEntryStart
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CALL sbfsCopyWord
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SETD.0 SbfsEntryEnd
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SETD.2 SbfsEntryStart
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CALL sbfsSetWord
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PSHD.3
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POPD.0
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DPUP.0 0d03
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SETD.1 SbfsScratch
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CALL sbfsCopyWord
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SETD.0 SbfsEntryEnd
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SETD.2 SbfsScratch
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CALL sbfsAddWord
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PSHD.3
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POPD.0
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DPUP.0 0d05
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LDA.0
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BRA sbfsBoundsDone ; No part block on the end.
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SETD.0 SbfsEntryEnd
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SETD.2 SbfsOne
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CALL sbfsAddWord
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sbfsBoundsDone:
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RET
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; Finds a run of SbfsWantBlocks free blocks and puts where it begins in SbfsFileStart.
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; Q is zero if there was room.
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;
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; First fit, walking the directory, because with files laid down contiguously the
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; directory already says which blocks are spoken for. There is no allocation table to
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; consult and none to keep right.
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sbfsAllocate:
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CALL sbfsFirstData
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sbfsAllocTry:
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SETD.0 SbfsCandEnd
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SETD.2 SbfsCandidate
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CALL sbfsSetWord
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SETD.0 SbfsCandEnd
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SETD.2 SbfsWantBlocks
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CALL sbfsAddWord
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; Past the end of the disk means there is nowhere left to look.
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SETD.0 SbfsDiskBlocks
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SETD.2 SbfsCandEnd
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CALL sbfsCompareWord
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BRC sbfsAllocNoRoom ; The disk is smaller than where this run would end.
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SETD.0 SbfsDirStart
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SETD.1 SbfsBlock
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CALL sbfsCopyWord
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SETD.0 SbfsDirBlocks
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DPUP.0 0d01
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LDA.0
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SETD.1 SbfsLeft
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STA.1
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sbfsAllocBlock:
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CALL sbfsReadBlock
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BNQ sbfsAllocFailed
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SETD.1 SbfsBuffer
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CALL sbfsBufferOut
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SETD.2 SbfsBuffer
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INIA 0d8
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SETD.1 SbfsCount
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STA.1
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sbfsAllocEntry:
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LDA.2
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INIB 0x01
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AND
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BRQ sbfsAllocNext ; A free entry holds nothing, so it is in nobody's way.
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CALL sbfsEntryBounds
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; The comparisons need DP2 for their own purposes, so where this entry is goes on the
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; Stack for the duration. Working it out again afterwards was the first way this was
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; written, and it was both longer and wrong.
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PSHD.2
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; Two runs overlap when each begins before the other ends.
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SETD.0 SbfsCandidate
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SETD.2 SbfsEntryEnd
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CALL sbfsCompareWord
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BNC sbfsAllocClear
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SETD.0 SbfsEntryStart
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SETD.2 SbfsCandEnd
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CALL sbfsCompareWord
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BNC sbfsAllocClear
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; They do overlap, so try again from the far end of whatever is in the way.
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POPD.2
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SETD.0 SbfsCandidate
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SETD.2 SbfsEntryEnd
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CALL sbfsSetWord
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BRI sbfsAllocTry
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sbfsAllocClear:
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POPD.2
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sbfsAllocNext:
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DPUP.2 0d32
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SETD.1 SbfsCount
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LDA.1
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DECA
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STA.1
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BNA sbfsAllocEntry
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SETD.0 SbfsBlock
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CALL sbfsStepWord
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SETD.1 SbfsLeft
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LDA.1
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DECA
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STA.1
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BNA sbfsAllocBlock
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; Nothing was in the way, so this is where it goes.
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SETD.0 SbfsFileStart
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SETD.2 SbfsCandidate
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CALL sbfsSetWord
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RSTA
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RSTB
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CCF
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ADD
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RET
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sbfsAllocNoRoom:
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sbfsAllocFailed:
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RSTA
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INIB 0d1
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CCF
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ADD
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RET
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; The two byte number at DP0 becomes the one at DP2. Written destination first, so that a
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; call reads the way an assignment does. sbfsCopyWord goes the other way, source first,
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; which is a difference worth keeping in mind: getting it backwards here quietly destroyed
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; a value that had just been worked out.
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sbfsSetWord:
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LDA.2
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STA.0
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INCD.2
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INCD.0
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LDA.2
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STA.0
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RET
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; The two byte number at DP0 becomes itself less the one at DP2.
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sbfsSubWord:
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DPUP.0 0d01
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DPUP.2 0d01
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LDA.0
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LDB.2
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CCF
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SUB
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MVQA
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STA.0
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DPDN.0 0d01
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DPDN.2 0d01
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LDA.0
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LDB.2
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SUB ; Borrows in from the low half.
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MVQA
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STA.0
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RET
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; How many blocks a file of SbfsFileBlocks and SbfsFileTail actually occupies, into
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; SbfsWantBlocks. A file of nothing occupies none.
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sbfsFileExtent:
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SETD.0 SbfsWantBlocks
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SETD.2 SbfsFileBlocks
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CALL sbfsSetWord
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SETD.0 SbfsFileTail
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LDA.0
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BRA sbfsExtentDone
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SETD.0 SbfsWantBlocks
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SETD.2 SbfsOne
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CALL sbfsAddWord
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sbfsExtentDone:
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RET
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; Makes a file. DP0 names it, and SbfsFileBlocks with SbfsFileTail say how big it is,
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; which has to be settled before it is made because nothing here can grow one afterwards.
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; Q is zero if it was made, and then SbfsFileStart says where its blocks are.
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sbfsCreate:
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SETD.1 SbfsWanted
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CALL sbfsKeepName
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CALL sbfsFileExtent
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CALL sbfsAllocate
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BNQ sbfsCreateFailed
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; Walk the directory for an entry nobody is using.
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SETD.0 SbfsDirStart
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SETD.1 SbfsBlock
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CALL sbfsCopyWord
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SETD.0 SbfsDirBlocks
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DPUP.0 0d01
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||||
LDA.0
|
||||
SETD.1 SbfsLeft
|
||||
STA.1
|
||||
|
||||
sbfsCreateBlock:
|
||||
CALL sbfsReadBlock
|
||||
BNQ sbfsCreateFailed
|
||||
SETD.1 SbfsBuffer
|
||||
CALL sbfsBufferOut
|
||||
SETD.2 SbfsBuffer
|
||||
INIA 0d8
|
||||
SETD.1 SbfsCount
|
||||
STA.1
|
||||
|
||||
sbfsCreateEntry:
|
||||
LDA.2
|
||||
INIB 0x01
|
||||
AND
|
||||
BRQ sbfsCreateFill ; This one is free.
|
||||
DPUP.2 0d32
|
||||
SETD.1 SbfsCount
|
||||
LDA.1
|
||||
DECA
|
||||
STA.1
|
||||
BNA sbfsCreateEntry
|
||||
|
||||
SETD.0 SbfsBlock
|
||||
CALL sbfsStepWord
|
||||
SETD.1 SbfsLeft
|
||||
LDA.1
|
||||
DECA
|
||||
STA.1
|
||||
BNA sbfsCreateBlock
|
||||
|
||||
sbfsCreateFull:
|
||||
RSTA
|
||||
INIB 0d1
|
||||
CCF
|
||||
ADD ; Every entry is taken.
|
||||
RET
|
||||
|
||||
sbfsCreateFill:
|
||||
; DP2 is on the entry. Fill it in, then put the whole block back on the disk.
|
||||
PSHD.2
|
||||
POPD.3
|
||||
INIA 0x01
|
||||
STA.3 ; In use.
|
||||
|
||||
PSHD.3
|
||||
POPD.1
|
||||
DPUP.1 0d01
|
||||
SETD.0 SbfsFileStart
|
||||
CALL sbfsCopyWord
|
||||
|
||||
PSHD.3
|
||||
POPD.1
|
||||
DPUP.1 0d03
|
||||
SETD.0 SbfsFileBlocks
|
||||
CALL sbfsCopyWord
|
||||
|
||||
PSHD.3
|
||||
POPD.1
|
||||
DPUP.1 0d05
|
||||
SETD.0 SbfsFileTail
|
||||
LDA.0
|
||||
STA.1
|
||||
|
||||
PSHD.3
|
||||
POPD.1
|
||||
DPUP.1 0d06
|
||||
SETD.0 SbfsWanted
|
||||
INIA 0d22
|
||||
SETD.2 SbfsCount
|
||||
STA.2
|
||||
sbfsCreateName:
|
||||
LDA.0
|
||||
STA.1
|
||||
INCD.0
|
||||
INCD.1
|
||||
LDA.2
|
||||
DECA
|
||||
STA.2
|
||||
BNA sbfsCreateName
|
||||
|
||||
SETD.1 SbfsBuffer
|
||||
CALL sbfsBufferIn
|
||||
CALL sbfsWriteBlock
|
||||
BNQ sbfsCreateFailed
|
||||
|
||||
; The free count is a note rather than the truth, but it should still be kept right.
|
||||
RSTA
|
||||
SETD.0 SbfsBlock
|
||||
STA.0
|
||||
INCD.0
|
||||
STA.0
|
||||
CALL sbfsReadBlock
|
||||
BNQ sbfsCreateFailed
|
||||
SETD.1 SbfsBuffer
|
||||
CALL sbfsBufferOut
|
||||
SETD.0 SbfsBuffer
|
||||
DPUP.0 0d12
|
||||
SETD.2 SbfsWantBlocks
|
||||
CALL sbfsSubWord
|
||||
SETD.1 SbfsBuffer
|
||||
CALL sbfsBufferIn
|
||||
CALL sbfsWriteBlock
|
||||
RET
|
||||
|
||||
sbfsCreateFailed:
|
||||
RSTA
|
||||
INIB 0d1
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
; Writes a file that sbfsCreate made, from Data Memory at DP1. Q is zero if it worked.
|
||||
;
|
||||
; Whole blocks go out whole, so whatever follows the file in Data Memory ends up in the
|
||||
; unused tail of its last block. That is harmless, since the tail in the entry says where
|
||||
; the file stops, but it does mean a block can hold a little of whatever was next to it.
|
||||
sbfsWriteFile:
|
||||
PSHD.1
|
||||
POPD.3
|
||||
SETD.0 SbfsBlock
|
||||
SETD.2 SbfsFileStart
|
||||
CALL sbfsSetWord
|
||||
CALL sbfsFileExtent
|
||||
SETD.0 SbfsWantBlocks
|
||||
DPUP.0 0d01
|
||||
LDA.0
|
||||
SETD.1 SbfsLeft
|
||||
STA.1
|
||||
BRA sbfsWriteDone ; A file of nothing has nothing to write.
|
||||
|
||||
sbfsWriteLoop:
|
||||
PSHD.3
|
||||
POPD.1
|
||||
CALL sbfsBufferIn
|
||||
CALL sbfsWriteBlock
|
||||
BNQ sbfsWriteFailed
|
||||
DPUP.3 0xFF
|
||||
DPUP.3 0x01
|
||||
SETD.0 SbfsBlock
|
||||
CALL sbfsStepWord
|
||||
SETD.0 SbfsLeft
|
||||
LDA.0
|
||||
DECA
|
||||
STA.0
|
||||
BNA sbfsWriteLoop
|
||||
|
||||
sbfsWriteDone:
|
||||
RSTA
|
||||
RSTB
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
sbfsWriteFailed:
|
||||
RSTA
|
||||
INIB 0d1
|
||||
CCF
|
||||
ADD
|
||||
RET
|
||||
|
||||
; Copies a whole block from Data Memory at DP1 into the disk's buffer, which is the other
|
||||
; way round from sbfsBufferOut.
|
||||
sbfsBufferIn:
|
||||
INIA 0d1
|
||||
OUTA 0xE0
|
||||
PSHD.1
|
||||
POPA
|
||||
POPB
|
||||
OUTB 0xE1
|
||||
OUTA 0xE2
|
||||
INIA 0d3
|
||||
OUTA 0xE3
|
||||
RSTA
|
||||
OUTA 0xE4
|
||||
OUTA 0xE5
|
||||
INIA 0x01
|
||||
OUTA 0xE6
|
||||
RSTA
|
||||
OUTA 0xE7
|
||||
INIA 0x01
|
||||
OUTA 0xE8
|
||||
RET
|
||||
|
||||
; Puts the disk's buffer down as the block named by SbfsBlock. Q is zero if it worked.
|
||||
sbfsWriteBlock:
|
||||
SETD.0 SbfsBlock
|
||||
LDA.0
|
||||
OUTA 0x20
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0x21
|
||||
INIA 0x02
|
||||
OUTA 0x22
|
||||
INA 0x23
|
||||
INIB 0x02
|
||||
AND
|
||||
RET
|
||||
|
||||
; Reads the block named by SbfsBlock into the disk's buffer. Q is zero if it worked.
|
||||
sbfsReadBlock:
|
||||
SETD.0 SbfsBlock
|
||||
LDA.0
|
||||
OUTA 0x20
|
||||
INCD.0
|
||||
LDA.0
|
||||
OUTA 0x21
|
||||
INIA 0x01
|
||||
OUTA 0x22
|
||||
INA 0x23
|
||||
INIB 0x02
|
||||
AND ; Q is the error bit, so zero means it worked.
|
||||
RET
|
||||
|
||||
; Copies the disk's buffer, a whole block of it, to Data Memory at DP1.
|
||||
sbfsBufferOut:
|
||||
INIA 0d3
|
||||
OUTA 0xE0
|
||||
RSTA
|
||||
OUTA 0xE1
|
||||
OUTA 0xE2
|
||||
INIA 0d1
|
||||
OUTA 0xE3
|
||||
PSHD.1
|
||||
POPA
|
||||
POPB
|
||||
OUTB 0xE4
|
||||
OUTA 0xE5
|
||||
INIA 0x01
|
||||
OUTA 0xE6
|
||||
RSTA
|
||||
OUTA 0xE7 ; A whole block.
|
||||
INIA 0x01
|
||||
OUTA 0xE8
|
||||
RET
|
||||
|
||||
; Two bytes from DP0 to DP1, most significant first, the way every number on a SplitBit
|
||||
; disk is stored.
|
||||
sbfsCopyWord:
|
||||
LDA.0
|
||||
STA.1
|
||||
INCD.0
|
||||
INCD.1
|
||||
LDA.0
|
||||
STA.1
|
||||
RET
|
||||
|
||||
; Adds one to the two byte number at DP0.
|
||||
sbfsStepWord:
|
||||
DPUP.0 0d01
|
||||
LDA.0
|
||||
INCA
|
||||
STA.0
|
||||
BNC sbfsStepDone ; It did not wrap, so the high byte is untouched.
|
||||
DPDN.0 0d01
|
||||
LDA.0
|
||||
INCA
|
||||
STA.0
|
||||
sbfsStepDone:
|
||||
RET
|
||||
|
||||
; The two byte number at DP0 becomes itself plus the one at DP2. Only memory changes, so
|
||||
; it survives the return: a routine cannot hand back a pointer or a register.
|
||||
sbfsAddWord:
|
||||
DPUP.0 0d01
|
||||
DPUP.2 0d01
|
||||
LDA.0
|
||||
LDB.2
|
||||
CCF
|
||||
ADD
|
||||
MVQA
|
||||
STA.0
|
||||
DPDN.0 0d01
|
||||
DPDN.2 0d01
|
||||
LDA.0
|
||||
LDB.2
|
||||
ADD ; Carries in from the low half. Nothing between the two touches it.
|
||||
MVQA
|
||||
STA.0
|
||||
RET
|
||||
|
||||
; Compares the two byte number at DP0 with the one at DP2. Q is zero if they are equal,
|
||||
; and the Carry Flag is set if the one at DP0 is the smaller. Both come back, because
|
||||
; neither Q nor the Status register is put back by a return.
|
||||
sbfsCompareWord:
|
||||
LDA.0
|
||||
LDB.2
|
||||
CCF
|
||||
SUB ; The high bytes settle it unless they are the same.
|
||||
BNQ sbfsCompareDone
|
||||
INCD.0
|
||||
INCD.2
|
||||
LDA.0
|
||||
LDB.2
|
||||
CCF
|
||||
SUB
|
||||
sbfsCompareDone:
|
||||
RET
|
||||
|
||||
; The byte at DP0 against the byte at DP2. Q is zero if they are the same.
|
||||
sbfsSameByte:
|
||||
LDA.0
|
||||
LDB.2
|
||||
XOR
|
||||
RET
|
||||
|
||||
#Data
|
||||
|
||||
SbfsMagic:
|
||||
"SBFS"
|
||||
|
||||
SbfsDirStart:
|
||||
0x00 0x00
|
||||
SbfsDirBlocks:
|
||||
0x00 0x00
|
||||
SbfsFileStart:
|
||||
0x00 0x00
|
||||
SbfsFileBlocks:
|
||||
0x00 0x00
|
||||
SbfsFileTail:
|
||||
0x00
|
||||
SbfsBlock:
|
||||
0x00 0x00
|
||||
SbfsDiskBlocks:
|
||||
0x00 0x00
|
||||
SbfsWantBlocks:
|
||||
0x00 0x00
|
||||
SbfsCandidate:
|
||||
0x00 0x00
|
||||
SbfsCandEnd:
|
||||
0x00 0x00
|
||||
SbfsEntryStart:
|
||||
0x00 0x00
|
||||
SbfsEntryEnd:
|
||||
0x00 0x00
|
||||
SbfsScratch:
|
||||
0x00 0x00
|
||||
SbfsOne:
|
||||
0x00 0x01
|
||||
SbfsCount:
|
||||
0x00
|
||||
SbfsLeft:
|
||||
0x00
|
||||
|
||||
SbfsWanted:
|
||||
#Reserve 0d22
|
||||
|
||||
SbfsBuffer:
|
||||
#Reserve 0d256
|
||||
Reference in New Issue
Block a user