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Little strdup optimisation
-12 bytes on disk -20 cycles per strdup -6 cycles per strlen called from strdup
This commit is contained in:
Colin Leroy-Mira
parent
169c9c0da0
commit
3a439e0e1b
@ -7,13 +7,13 @@
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.export _strcspn
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.import popptr1, _strlen
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.importzp ptr1, ptr2, tmp1, tmp2
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.importzp ptr1, ptr4, tmp1, tmp2
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_strcspn:
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jsr _strlen ; get length in a/x and transfer s2 to ptr2
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jsr _strlen ; get length in a/x and transfer s2 to ptr4
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; Note: It does not make sense to
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; have more than 255 test chars, so
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; we don't support a high byte here! (ptr2+1 is
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; we don't support a high byte here! (ptr4+1 is
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; also unchanged in strlen then (important!))
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; -> the original implementation also
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; ignored this case
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@ -38,7 +38,7 @@ checkNext:
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iny
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check: cpy tmp1 ; compare with length of test character string
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beq endOfTestChars
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cmp (ptr2),y ; found matching char?
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cmp (ptr4),y ; found matching char?
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bne checkNext
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leave: txa ; restore position of finding
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@ -1,85 +1,62 @@
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;
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; Ullrich von Bassewitz, 18.07.2000
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; Colin Leroy-Mira, 05.01.2024
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;
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; char* __fastcall__ strdup (const char* S);
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;
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; Note: The code knowns which zero page locations are used by malloc.
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; Note: The code knowns which zero page locations are used by malloc,
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; memcpy and strlen.
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;
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.importzp sp, tmp1, ptr4
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.import pushax, decsp4, incsp4
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.import _strlen, _malloc, _memcpy
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.importzp ptr2, ptr3, ptr4, tmp1, tmp2, tmp3
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.import _strlen_ptr4, _malloc, _memcpy, pushax
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.export _strdup
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.macpack cpu
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.macpack generic
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_strdup:
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; Get length (and store source in ptr4)
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sta ptr4
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stx ptr4+1
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stx tmp1 ; Backup high byte, which
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jsr _strlen_ptr4 ; strlen may increment
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; Since we need some place to store the intermediate results, allocate a
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; stack frame. To make this somewhat more efficient, create the stackframe
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; as needed for the final call to the memcpy function.
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pha ; decsp will destroy A (but not X)
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jsr decsp4 ; Target/source
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; Store the pointer into the source slot
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ldy #1
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txa
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sta (sp),y
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pla
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.if (.cpu .bitand CPU_ISET_65SC02)
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sta (sp)
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; Add null byte for terminator
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.if (.cpu .bitand ::CPU_ISET_65SC02)
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inc a
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.else
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dey
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sta (sp),y
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clc
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adc #1
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.endif
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; Get length of S (which is still in a/x)
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jsr _strlen
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; Calculate strlen(S)+1 (the space needed)
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add #1
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bcc @L1
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bne :+
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inx
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; Save the space we're about to allocate in ptr4
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@L1: sta ptr4
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stx ptr4+1
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; Allocate memory. _malloc will not use ptr4
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; Store length
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: sta tmp2
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stx tmp3
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; Allocate memory
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jsr _malloc
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; Store the result into the target stack slot
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ldy #2
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sta (sp),y ; Store low byte
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sta tmp1
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txa ; Get high byte
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iny
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sta (sp),y ; Store high byte
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; Check for a NULL pointer
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ora tmp1
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; Check for NULL
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bne :+
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cpx #$00
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beq OutOfMemory
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; Copy the string. memcpy will return the target string which is exactly
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; what we need here. It will also drop the allocated stack frame.
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; Push dest
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: jsr pushax
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; Push source
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lda ptr4
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ldx ptr4+1 ; Load size
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jmp _memcpy ; Copy string, drop stackframe
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ldx tmp1
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jsr pushax
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; Out of memory, return NULL (A = 0)
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; Push length
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lda tmp2
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ldx tmp3
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; Copy and return the dest pointer
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jmp _memcpy
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OutOfMemory:
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tax
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jmp incsp4 ; Drop stack frame
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rts
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@ -2,19 +2,20 @@
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; Ullrich von Bassewitz, 31.05.1998
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;
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; Note: strspn & strcspn call internally this function and rely on
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; the usage of only ptr2 here! Keep in mind when appling changes
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; the usage of only ptr4 here! Keep in mind when appling changes
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; and check the other implementations too!
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;
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; size_t __fastcall__ strlen (const char* s);
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;
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.export _strlen
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.importzp ptr2
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.export _strlen, _strlen_ptr4
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.importzp ptr4
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.macpack cpu
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_strlen:
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sta ptr2 ; Save s
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stx ptr2+1
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sta ptr4 ; Save s
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stx ptr4+1
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_strlen_ptr4:
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.if (.cpu .bitand ::CPU_ISET_HUC6280)
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clx
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cly
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@ -27,11 +28,11 @@ _strlen:
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.endif
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.endif
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L1: lda (ptr2),y
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L1: lda (ptr4),y
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beq L9
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iny
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bne L1
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inc ptr2+1
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inc ptr4+1
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inx
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bne L1
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@ -7,13 +7,13 @@
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.export _strspn
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.import popptr1, _strlen
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.importzp ptr1, ptr2, tmp1, tmp2
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.importzp ptr1, ptr4, tmp1, tmp2
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_strspn:
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jsr _strlen ; get length in a/x and transfer s2 to ptr2
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jsr _strlen ; get length in a/x and transfer s2 to ptr4
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; Note: It does not make sense to
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; have more than 255 test chars, so
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; we don't support a high byte here! (ptr2+1 is
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; we don't support a high byte here! (ptr4+1 is
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; also unchanged in strlen then (important!))
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; -> the original implementation also
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; ignored this case
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@ -38,7 +38,7 @@ checkNext:
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iny
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check: cpy tmp1 ; compare with length of test character string
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beq leave
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cmp (ptr2),y ; found matching char?
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cmp (ptr4),y ; found matching char?
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bne checkNext
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foundTestChar:
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