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Attempt to describe purpose of source code in dsksav.s

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This commit is contained in:
Sebastian Rasmussen
2019-10-27 14:24:10 +01:00
parent 07b5d101bd
commit 55383ce528
1 changed files with 19 additions and 13 deletions
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32
src/cmd/dsksav.s
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@@ -1,26 +1,32 @@
" dsksav
iof
hlt
dzm track
-640
" Copies the entire file system (except system image and
" swap area) from side 1 of the disk onto same location
" on side 0.
"
" I.e. copies the first 6400 blocks from side 1 to side 0.
iof " disable interrupts
hlt " halt the computer!
dzm track " start copying from block address 0
-640 " transfer 640 chunks of 10 blocks each
dac c1
1:
lac track
lac track " read chunk of blocks starting at block "track" on side 1
jms dskrd1
lac track
lac track " write chunk of blocks starting at block "track" on side 0
jms dskwr0
lac track
lac track " proceed to next chunk (of 10 blocks)
tad d10
dac track
isz c1
jmp 1b
isz c1 " increment chunks transferred, if there chunks remaining
jmp 1b " ...loop and transfer the next chunk
hlt
sys exit
hlt " ...otherwise halt the computer!
sys exit " call exit system call
track: 0
c1: 0
track: 0 " block address of chunk to transfer
c1: 0 " number of chunks remaining
d10: 10