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Reduced the size of the moveinit subroutine.

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Made other changes that were recommended by Oliver.
* Changed its name from move_init to moveinit.
* Used self-modifying code in the subroutine.
* The INIT segment doesn't need to be optional (it's used by the start-up file).
This commit is contained in:
Greg King
2015-10-07 14:56:14 -04:00
parent 074e10d288
commit 8a880580dc
4 changed files with 25 additions and 42 deletions
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41
libsrc/common/moveinit.s
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@@ -1,16 +1,19 @@
;
; 2015-10-04, Greg King
; 2015-10-07, Greg King
;
.export move_init
.export moveinit
.import __INIT_LOAD__, __INIT_RUN__, __INIT_SIZE__ ; Linker-generated
.importzp init_load_, init_run_
.macpack cpu
.macpack generic
; Put this in the DATA segment because it is self-modifying code.
.data
; Move the INIT segment from where it was loaded (over the bss segments)
; into where it must be run (in the heap). The two areas might overlap; and,
; the segment is moved upwards. Therefore, this code starts at the highest
@@ -19,36 +22,24 @@
; carry. Both the low-byte sums and the carries will be done when the pointers
; are indexed by the .Y register.
move_init:
lda #<__INIT_LOAD__
ldx #>__INIT_LOAD__ + >__INIT_SIZE__
sta init_load_
stx init_load_+1
lda #<__INIT_RUN__
ldx #>__INIT_RUN__ + >__INIT_SIZE__
sta init_run_
stx init_run_+1
moveinit:
; First, move the last, partial page.
; Then, move all of the full pages.
ldx #>__INIT_SIZE__ + 1 ; number of pages, including partial
ldy #<__INIT_SIZE__ ; size of partial page
.if .cpu & CPU_ISET_65SC02
bra L3
.else
jmp L3
.endif
ldx #>__INIT_SIZE__ + (<__INIT_SIZE__ <> 0) ; number of pages, including partial
L1: dec init_load_+1
dec init_run_+1
L2: dey
lda (init_load_),y
sta (init_run_),y
L1: dey
init_load:
lda __INIT_LOAD__ + (__INIT_SIZE__ & $FF00) - $0100 * (<__INIT_SIZE__ = 0),y
init_run:
sta __INIT_RUN__ + (__INIT_SIZE__ & $FF00) - $0100 * (<__INIT_SIZE__ = 0),y
tya
L3: bnz L2 ; page not finished
bnz L1 ; page not finished
dec init_load+2
dec init_run+2
dex
bnz L1 ; move next page
rts