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Better docs in loder code listing

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This commit is contained in:
Ross Wilson
2016-02-01 16:51:58 +07:00
parent 918cd9344c
commit 7593981532
1 changed files with 9 additions and 8 deletions
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pyasm/pyasm
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@@ -236,12 +236,13 @@ BlockLoader = [
# ; word which follows the data words. The checksum is calculated with 16bit
# ; integers, incrementing the sum whenever the 16bit value overflows.
# ;
# ; The end of the load is signalled by a block with a negative starting address.
# ; The end of the load is signalled by a block with a
# ; starting address 0177777.
# ;
# ; Disassembled from the 40tp_simpleDisplay.ptp image file.
# ;
# org 003700 ;
# cksum equ .-1 ;checksum stored here (before loader)
# cksum equ .-1 ;checksum stored here (at 003677)
0001032, # 003700 rcf ;
0013740, # 003701 jmp patch ;go decide TTY or PTR, clear AC
0023677, # 003702 ndpatch dac cksum ;zero checksum, AC is zero (from patch)
@@ -254,7 +255,7 @@ BlockLoader = [
0023776, # 003711 dac ldaddr ;
0077730, # 003712 sam neg1 ;
0013715, # 003713 jmp rdblock ;
0000000, # 003714 hlt ;if load address is -1, halt - finished
0000000, # 003714 hlt ;if load address is -1, finished
0037750, # 003715 rdblock jms rdword ;now read block to load address
0123776, # 003716 dac *ldaddr ;
0037731, # 003717 jms dosum ;
@@ -271,11 +272,11 @@ BlockLoader = [
# ;Compute checksum. Word to sum in AC.
# ;------------------------
0017720, # 003731 dosum bss 1 ;
0100010, # 003732 cll ;
0067677, # 003733 add cksum ;
0002004, # 003734 lsz ;
0100004, # 003735 iac ;
0023677, # 003736 dac cksum ;
0100010, # 003732 cll ; clear link
0067677, # 003733 add cksum ; add AC to checksum
0002004, # 003734 lsz ; if overflow:
0100004, # 003735 iac ; increment new checksum
0023677, # 003736 dac cksum ; save new checksum
0113731, # 003737 jmp *dosum ;
# ;------------------------
# ;Decide what input device we are using, PTR or TTY.