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Squeezed a few cycles/bytes out of tolower and toupper.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@690 b7a2c559-68d2-44c3-8de9-860c34a00d81
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cuz 2001-04-19 06:46:01 +00:00
parent 72e27092d4
commit dccc89edae
2 changed files with 8 additions and 14 deletions
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13
libsrc/common/tolower.s
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@ -10,13 +10,10 @@
_tolower:
tay ; Get C into Y
lda __ctype,y ; Get character classification
and #$02 ; Is this an upper case char?
beq L1 ; Jump if no
lsr a
lsr a ; Get bit 1 (upper case char) into carry
tya ; Get char back into A
sec
sbc __cdiff ; make lower case char
rts ; CC are set
L1: tya ; Get char back into A
rts ; CC are set
bcc L9 ; Jump if no upper case char
sbc __cdiff ; make lower case char (carry already set)
L9: rts ; CC are set

9
libsrc/common/toupper.s
View File

@ -10,13 +10,10 @@
_toupper:
tay ; Get c into Y
lda __ctype,y ; Get character classification
and #$01 ; Mask lower char bit
beq L1 ; Jump if not lower char
lsr a ; Get bit 0 (lower char) into carry
tya ; Get C back into A
bcc L9 ; Jump if not lower char
clc
adc __cdiff ; make upper case char
rts ; CC are set
L1: tya ; Get C back
rts ; CC are set
L9: rts ; CC are set