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[atari] Optimize fd routines #340

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Merged
mysterymath merged 2 commits into from
Jun 19, 2024
Merged

[atari] Optimize fd routines #340

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7aa8659
[atari] Optimize fd routines
pfusik Jun 17, 2024
00fccc3
fixup! [atari] Optimize fd routines
pfusik Jun 19, 2024
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13 changes: 4 additions & 9 deletions mos-platform/atari8-common/fdtable.s
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Original file line number Diff line number Diff line change
Expand Up @@ -31,22 +31,18 @@ fdtoiocb_down:
bne inval
cmp #MAX_FD_INDEX
bcs inval
tax
lda fd_index,x ; get index
tay
lda #$ff
sta fd_index,x ; clear entry
tya
lda fd_index,y ; get index
asl a ; create index into fd table
asl a
tax
lda #$ff
sta fd_index,y ; clear entry
cmp fd_table+ft_iocb,x ; entry in use?
beq inval ; no, return error
lda fd_table+ft_usa,x ; get usage counter
beq ok_notlast ; 0? (shouldn't happen)
sec
sbc #1 ; decr usage counter
sbc #1 ; decr usage counter, C=1
sta fd_table+ft_usa,x
retiocb:php
txa
Expand Down Expand Up @@ -109,8 +105,7 @@ fddecusage:
beq ret ; no, do nothing
lda fd_table+ft_usa,x ; get usage counter
beq ret ; 0? should not happen
sec
sbc #1 ; decrement by one
sbc #1 ; decrement by one, C=1
sta fd_table+ft_usa,x
bne ret ; not 0
lda #$ff ; 0, table entry unused now
Expand Down
13 changes: 6 additions & 7 deletions mos-platform/atari8-common/getfd.s
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Original file line number Diff line number Diff line change
Expand Up @@ -22,17 +22,17 @@
; get fd_table entry in A
; return C = 0/1 for OK/error
; return fd_index entry in A if OK
; return ft_table entry in Y (for getfd below)
; registers destroyed
fdt_to_fdi:

tay
lda #$ff
tax
inx
loop: cmp fd_index,x
loop: inx
cmp fd_index,x
beq found
inx
cpx #MAX_FD_INDEX
cpx #MAX_FD_INDEX-1
bcc loop
rts

Expand All @@ -48,15 +48,14 @@ found: tya
; A - fd_table entry
; return C = 0/1 for OK/error
; returns fd in A if OK
; registers destroyed, tmp1 destroyed
; registers destroyed
getfd:

sta __rc10 ; save fd_table entry
jsr fdt_to_fdi
bcs error

pha
lda __rc10
tya
asl a
asl a ; also clears C
tax
Expand Down