explained all similarities >3, some minor cleanups

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FeralChild64 committed 2019-09-10 18:28:30 +02:00
1 parent 53e4babbe3
commit 49e8b75b85
44 files changed
+208 -12

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+1 -1
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@@ -159,7 +159,7 @@
.label SAT = $26D // $26D-$276, secondary addresses (table, 10 bytes)
.label KEYD = $277 // $277-$280, keyboard buffer
.label MEMSTR = $281 // $281-$282, start of BASIC memory
.label MEMEND = $283 // $283-$284, NOTE: Mapping the 64 erroneously has the hex as $282 (DEC is correct), name seems to be mistaken too
.label MEMSIZK = $283 // $283-$284, NOTE: Mapping the 64 erroneously has the hex as $282 (DEC is correct)
.label TIMOUT = $285 // IEEE-488 timeout
.label COLOR = $286 // current text foreground color
.label GDCOL = $287 // color of character under cursor
+4 -4
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@@ -12,13 +12,13 @@ MEMTOP:
bcc memtop_set
ldy MEMEND+1
ldx MEMEND+0
ldy MEMSIZK+1
ldx MEMSIZK+0
rts
memtop_set:
sty MEMEND+1
stx MEMEND+0
sty MEMSIZK+1
stx MEMSIZK+0
rts
+4 -4
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@@ -61,14 +61,14 @@ ramtas_l2:
ldx #>$0400
stx HIBASE
// Work out RAM size and put in MEMSTR and MEMEND
// Work out RAM size and put in MEMSTR and MEMSIZK
// "Compute's Mapping the 64", p54
// http://unusedino.de/ec64/technical/project64/mapping_c64.html
ldx #>$0800
stx MEMSTR+1
ldx #$00
stx MEMSTR+0
stx MEMEND+0
stx MEMSIZK+0
// Try to modify $8000, if it fails then RAM ends at $7FFF, else $9FFF
lda $8000
eor #$FF
@@ -79,12 +79,12 @@ ramtas_l2:
beq ramtas_32K_RAM
sta $8000
ldx #$A0
stx MEMEND+1
stx MEMSIZK+1
jmp ramtas_RAM_sized
ramtas_32K_RAM:
sta $8000 // in case RAM is hiding beneath a ROM
ldx #$80
stx MEMEND+1
stx MEMSIZK+1
// Fall through
ramtas_RAM_sized: