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a BIT of 65C02 optimisations

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Use BIT immediate instead of AND when reloading A is required
afterwards.
Add an fread unit test as the optimisation touches fread.
Sprinkle a few zero page indexed while we're at it.
This commit is contained in:
Colin Leroy-Mira
2024-02-01 20:05:57 +01:00
parent 2a03e5d8c9
commit 1fab179cb4
5 changed files with 145 additions and 10 deletions
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32
libsrc/common/fread.s
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@@ -20,6 +20,7 @@
.include "_file.inc"
.macpack generic
.macpack cpu
; ------------------------------------------------------------------------
; Code
@@ -47,13 +48,21 @@
ldy #_FILE::f_flags
lda (file),y
.if (.cpu .bitand ::CPU_ISET_65SC02)
bit #_FOPEN ; Is the file open?
.else
and #_FOPEN ; Is the file open?
.endif
beq @L1 ; Branch if no
; Check if the stream is in an error state
.if (.cpu .bitand ::CPU_ISET_65SC02)
bit #_FERROR
.else
lda (file),y ; get file->f_flags again
and #_FERROR
.endif
beq @L2
; File not open or in error state
@@ -65,11 +74,19 @@
; Remember if we have a pushed back character and reset the flag.
@L2: tax ; X = 0
@L2: .if (.cpu .bitand ::CPU_ISET_65SC02)
ldx #$00
bit #_FPUSHBACK
.else
tax ; X = 0
lda (file),y
and #_FPUSHBACK
.endif
beq @L3
.if (.not .cpu .bitand ::CPU_ISET_65SC02)
lda (file),y
.endif
and #<~_FPUSHBACK
sta (file),y ; file->f_flags &= ~_FPUSHBACK;
inx ; X = 1
@@ -118,12 +135,20 @@
; Copy the buffer pointer into ptr1, and increment the pointer value passed
; to read() by one, so read() starts to store data at buf+1.
.if (.cpu .bitand ::CPU_ISET_65SC02)
lda (sp)
sta ptr1
add #1
sta (sp)
ldy #1
.else
ldy #0
lda (sp),y
sta ptr1
add #1
sta (sp),y
iny
.endif
lda (sp),y
sta ptr1+1
adc #0
@@ -134,8 +159,12 @@
ldy #_FILE::f_pushback
lda (file),y
.if (.cpu .bitand ::CPU_ISET_65SC02)
sta (ptr1) ; *buf = file->f_pushback;
.else
ldy #0
sta (ptr1),y ; *buf = file->f_pushback;
.endif
; Restore the low byte of count and decrement count by one. This may result
; in count being zero, so check for that.
@@ -210,4 +239,3 @@
.bss
save: .res 2
pb: .res 1