A2osX/SYS/KERNEL.S.STRING.txt
2018-11-21 14:08:11 +01:00

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NEW
PREFIX
AUTO 4,1
*/--------------------------------------
* # StrLen
* Returns Length of C-String
* ## C
* `int strlen ( char * str);`
* ## ASM
* `>LDYAI str`
* `>SYSCALL strlen`
* ## RETURN VALUE
* Y,A = String length
*\--------------------------------------
K.StrLen >STYA .1+1
ldy #0
tya
.1 ldx $ffff,y SELF MODIFIED
beq .8
iny
bne .1
inc
inc .1+2
bra .1
.8 rts
*/--------------------------------------
* # StrCat
* Concatenate strings
* ## C
* `char * strcat ( char * destination, const char * source );`
* ## ASM
* **In:**
* `>PUSHWI source`
* `>LDYAI destination`
* `>SYSCALL strcat`
* ## RETURN VALUE
* Y,A = destination
*\--------------------------------------
K.StrCat sec
.HS 90 BCC
*/--------------------------------------
* # StrCpy
* Copy string
* ## C
* `char * strcpy ( char * destination, const char * source );`
* ## ASM
* **In:**
* `>PUSHWI source`
* `>LDYAI destination`
* `>SYSCALL strcpy`
* ## RETURN VALUE
* Y,A = destination
*\--------------------------------------
K.StrCpy clc
pha
phy
jsr MEM.SPtr1PPtr2
bcc .2
.1 lda (ZPPtr1)
beq .2
inc ZPPtr1
bne .1
inc ZPPtr1+1
bra .1
.2 ldy #0
.3 lda (ZPPtr2),y
sta (ZPPtr1),y
beq .8
iny
bne .3
inc ZPPtr2+1
inc ZPPtr1+1
bra .3
.8 ply
pla
rts
*/--------------------------------------
* # StrUpr/StrLwr
* Convert string to UPPERCASE/lowercase
* ## C
* `int strupr ( char * str);`
* `int strlwr ( char * str);`
* ## ASM
* **In:**
* `>LDYAI str`
* `>SYSCALL strupr`
* `>SYSCALL strlwr`
* ## RETURN VALUE
* Uppercased/lowercased String in Buffer
* Y,A = str
*\--------------------------------------
K.StrUpr ldx #0
.HS 2C bit abs
K.StrLwr ldx #2
>STYA ZPPtr1
pha save Y,A to restore them at exit
phy
ldy #0
.1 lda (ZPPtr1),y
beq .8
cmp .9,x
bcc .2
cmp .9+1,x
bcs .2
eor #$20
sta (ZPPtr1),y
.2 iny
bne .1
inc ZPPtr1+1
bra .1
.8 ply
pla
rts
*--------------------------------------
.9 .AS "azAZ"
*/--------------------------------------
* # StrCmp
* Compare 2 strings
* ## C
* `int strcmp(const char *s1, const char *s2);`
* ## ASM
* **In:**
* `>PUSHWI s2`
* `>LDYAI s1`
* `>SYSCALL strcmp`
* ## RETURN VALUE
* CC : match
* CS : no match
* CC, Y,A=0
* CS, Y,A > 0 or < 0
*\--------------------------------------
K.StrCmp sec
.HS 90 BCC
*/--------------------------------------
* # StrCaseCmp
* Compare 2 strings, ignoring case
* ## C
* `int strcasecmp(const char *s1, const char *s2);`
* ## ASM
* **In:**
* `>PUSHWI s2`
* `>LDYAI s1`
* `>SYSCALL strcasecmp`
* ## RETURN VALUE
* CC : match
* CS : no match
* CC, Y,A=0
* CS, Y,A > 0 or < 0
*\--------------------------------------
K.StrCaseCmp clc
jsr MEM.SPtr1PPtr2
ldy #0
.1 lda (ZPPtr1),y
beq .7
jsr K.StrCaseCmp.toUpper
sta .2+1
lda (ZPPtr2),y
beq .9
jsr K.StrCaseCmp.toUpper
.2 eor #$ff SELF MODIFIED
bne .9
iny
bne .1
inc ZPPtr1+1
inc ZPPtr2+1
bra .1
.7 lda (ZPPtr2),y
bne .9
tay
.8 clc
rts
.9 sec
lda (ZPPtr1),y
sbc (ZPPtr2),y
ldy #0
sec
rts
*--------------------------------------
K.StrCaseCmp.toUpper
bcs .9
cmp #'a'
bcc .9
cmp #'z'+1
bcs .1
eor #$20
.1 clc
.9 rts
*--------------------------------------
MAN
SAVE USR/SRC/SYS/KERNEL.S.STRING
LOAD USR/SRC/SYS/KERNEL.S
ASM