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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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2
cfg/c64-overlay.cfg
View File

@ -46,7 +46,7 @@ SEGMENTS {
DATA: load = RAM, type = rw;
ZPSAVE: load = RAM, type = bss, define = yes;
BSS: load = RAM, type = bss, define = yes;
INIT: load = MOVE, run = RAM, type = ro, define = yes, optional = yes;
INIT: load = MOVE, run = RAM, type = ro, define = yes;
OVL1ADDR: load = OVL1ADDR, type = ro;
OVERLAY1: load = OVL1, type = ro, define = yes, optional = yes;
OVL2ADDR: load = OVL2ADDR, type = ro;

2
cfg/c64.cfg
View File

@ -25,7 +25,7 @@ SEGMENTS {
DATA: load = RAM, type = rw;
ZPSAVE: load = RAM, type = bss, define = yes;
BSS: load = RAM, type = bss, define = yes;
INIT: load = MOVE, run = RAM, type = ro, define = yes, optional = yes;
INIT: load = MOVE, run = RAM, type = ro, define = yes;
}
FEATURES {
CONDES: type = constructor,

22
libsrc/c64/crt0.s
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@ -3,12 +3,11 @@
;
.export _exit
.exportzp init_load_, init_run_
.export __STARTUP__ : absolute = 1 ; Mark as startup
.import initlib, donelib
.import move_init, zerobss, callmain
.import RESTOR, BSOUT, CLRCH
.import moveinit, zerobss, callmain
.import BSOUT
.import __HIMEM__ ; from configure file
.importzp ST
@ -19,13 +18,6 @@
; ------------------------------------------------------------------------
; Startup code
; Two zero-page pointers are needed before any zero-page stuff is saved.
; Choose locations that are not used by anything.
init_load_ := FREKZP
init_run_ := FREKZP+2
.segment "STARTUP"
Start:
@ -49,17 +41,17 @@ Start:
; Allow some re-entrancy by skipping the next task if it already was done.
; This often can let us rerun the program without reloading it.
ldx moveinit
ldx move_init
beq L0
; Move the INIT segment from where it was loaded (over ZPSAVE and BSS)
; into where it must be run (in the heap).
jsr move_init
dec moveinit ; set to false
jsr moveinit
dec move_init ; set to false
; Save space by putting the rest of the start-up code in the INIT segment,
; which can be re-used by the heap.
; which can be re-used by the heap and the C stack.
L0: jsr initstart
@ -134,7 +126,7 @@ L1: lda sp,x
mmusave:.res 1
spsave: .res 1
moveinit:
move_init:
.byte 1
.segment "ZPSAVE"

41
libsrc/common/moveinit.s
View File

@ -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