Apple-2-Tools/4cade
1
0
Fork 0
mirror of https://github.com/a2-4am/4cade.git synced 2024-06-06 12:29:30 +00:00
Code Issues Projects Releases Wiki Activity

fix typo and clarify comment

Browse Source
This commit is contained in:
4am 2020-11-09 19:44:53 -05:00
parent 68bb9e0454
commit 9e74cb1b6d
1 changed files with 6 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
src/ui.attract.shr.a
View File

@ -132,14 +132,14 @@ BlankSHR
stx SHADOW
; VIDHD-SPECIFIC HACK HERE!
; On the II/II+/IIe, all $C03x are aliases for $C030, i.e. the speaker.
; On the II/II+/IIe, all $C03x addresses are aliases for $C030, i.e. the speaker.
; Any single access of the speaker register requires a second access within a short
; time to balance the level if we want to avoid an audible click, which we do here.
; Since we can't read from SHADOW before writing to it (VidHD will crash the machine
; if we do that - ask us how we know), we have to balance the speaker access by
; accessing a speaker address explicitly because let's not make VIDHD angry.
; Hence the write to SPEAKER. Do not remove.
stx SPEAKER
; Since we can't read from SHADOW before writing to it (it returns random values on
; 8-bit machines, which VidHD interprets as invalid graphic modes and crashes hard),
; we instead balance the speaker access with a second write to the same speaker-
; aliased softswitch. Do not remove.
stx SHADOW
lsr ; clear $2000..$9FFF in auxmem
ldx #$80