Revert "Avoid unwanted i/o access."

Neither the original hardware type nor the alternative hardware type have any read and write i/o port share addresses. Therefore phantom reads aren't an issue with those hardware types.

This reverts commit ae5cb754fb.
This commit is contained in:
Oliver Schmidt 2022-08-19 10:13:05 +02:00
parent b3acd5b312
commit 40aba1d7b6
2 changed files with 12 additions and 23 deletions

View File

@ -17,15 +17,10 @@ XLEN = $BE52 ;length of command string-1.
XCNUM = $BE53 ;CI cmd no. (ext cmd - 0).
PBITS = $BE54 ;Command parameter bits.
XRETURN = $FF58 ;Known RTS instruction.
; have 6502 absolute indexed access phantom reads
; happen on page $bf to avoid unwanted i/o access
IndexOffset = $8f
InputByte = $c08e - IndexOffset
OutputByte = $c08d - IndexOffset
InputFlags = $c08b - IndexOffset
OutputFlags = $c087 - IndexOffset
InputByte = $c08e
OutputByte = $c08d
InputFlags = $c08b
OutputFlags = $c087
ReadBlockCommand = $01
WriteBlockCommand = $02
@ -81,10 +76,9 @@ DetectSlot:
asl
asl
asl
clc
adc #IndexOffset
tax
bcc Start ;always
clc
bcc Start
nextSlot:
dex
bne DetectSlot

View File

@ -19,14 +19,10 @@ IOError = $27
NoDevice = $28
WriteProtect = $2B
; have 6502 absolute indexed access phantom reads
; happen on page $bf to avoid unwanted i/o access
IndexOffset = $8f
InputByte = $c08e - IndexOffset
OutputByte = $c08d - IndexOffset
InputFlags = $c08b - IndexOffset
OutputFlags = $c087 - IndexOffset
InputByte = $c08e
OutputByte = $c08d
InputFlags = $c08b
OutputFlags = $c087
ResetCommand = $00
ReadBlockCommand = $01
@ -89,10 +85,9 @@ DetectSlot:
asl
asl
asl
clc
adc #IndexOffset
tax
bcc Init ;always
clc
bcc Init
nextSlot:
dex
bne DetectSlot