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Added size checking routine contributed by Marco van den Heuvel.

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git-svn-id: svn://svn.cc65.org/cc65/trunk@4565 b7a2c559-68d2-44c3-8de9-860c34a00d81
This commit is contained in:
uz 2010-02-01 07:07:24 +00:00
parent 5477e62e3a
commit 80b1dddb7f
1 changed files with 88 additions and 5 deletions
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91
libsrc/c64/c64-georam.s
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@ -3,6 +3,9 @@
; problems when statically linked.
;
; Ullrich von Bassewitz, 2002-11-29
;
; GEORAM page size checking routine by
; Marco van den Heuvel, 2010-01-21
;
.include "zeropage.inc"
@ -47,7 +50,7 @@ GR_PAGE_HI = $DFFF ; Page register high
.data
pagecount: .word 2048 ; Currently fixed
pagecount: .res 2 ; Number of available pages
.code
@ -59,9 +62,89 @@ pagecount: .word 2048 ; Currently fixed
;
INSTALL:
lda #<EM_ERR_OK
ldx #>EM_ERR_OK
; rts ; Run into UNINSTALL instead
tya
pha
ldx GR_WINDOW
cpx GR_WINDOW
bne @notpresent
inc GR_WINDOW
cpx GR_WINDOW
beq @notpresent
lda #4
jsr check
cpy GR_WINDOW
beq @has64k
lda #8
jsr check
cpy GR_WINDOW
beq @has128k
lda #16
jsr check
cpy GR_WINDOW
beq @has256k
lda #32
jsr check
cpy GR_WINDOW
beq @has512k
lda #64
jsr check
cpy GR_WINDOW
beq @has1024k
lda #128
jsr check
cpy GR_WINDOW
beq @has2048k
ldx #>16384
bne @setok
@has64k:
ldx #>256
bne @setok
@has128k:
ldx #>512
bne @setok
@has256k:
ldx #>1024
bne @setok
@has512k:
ldx #>2048
bne @setok
@has1024k:
ldx #>4096
bne @setok
@has2048k:
ldx #>8192
bne @setok
@notpresent:
pla
tay
lda #<EM_ERR_NO_DEVICE
ldx #>EM_ERR_NO_DEVICE
rts
@setok:
lda #0
sta pagecount
stx pagecount+1
pla
tay
lda #<EM_ERR_OK
ldx #>EM_ERR_OK
rts
check:
ldx #0
stx GR_PAGE_LO
stx GR_PAGE_HI
ldy GR_WINDOW
iny
sta GR_PAGE_HI
sty GR_WINDOW
ldx #0
stx GR_PAGE_HI
; rts ; Run into UNINSTALL instead
; ------------------------------------------------------------------------
; UNINSTALL routine. Is called before the driver is removed from memory.