Re: A86: can one program be on two pages?

To: assembly-86@lists.ticalc.org
Subject: Re: A86: can one program be on two pages?
From: rabidcow@juno.com
Date: Sat, 4 Jul 1998 21:19:10 -0700
Delivered-To: assembly-86-outgoing@towerguard.unix.edu.sollentuna.se
References: <5204d236.359ec4aa@aol.com>
Reply-To: assembly-86@lists.ticalc.org


On Sat, 4 Jul 1998 20:11:21 EDT TGaArdvark@aol.com writes:
>
>Then again, you could always just DISABLE THE INTERRUPTS first.

why not just stop arguing and try it?  this one doesn't quite work.  it
crashes on return.  help fix it, maybe?  (i use tasm by the way)  it's
also a bit messy 'cause i wasn't expecting to post it...

also - if you really need to read variables, use the rom slot for ram.

-josh

;big prog loader for programs up to 30k

_SET_ABS_SRC_ADDR       = $4647
_SET_MM_NUM_BYTES       = $464F
_create_string          = $472F
_inc2_ptr_ahl           = $4C3F
_SET_ABS_DEST_ADDR      = $5285
_mm_ldir                = $52ED
_conv_addr              = $4633
_delvar                 = $475F
_memory_error           = $4160

.org $d748
;save $c000-$d748
        ld hl,savedata-1
        rst 20h
        xor a
        ld hl,$C000
        call _SET_ABS_SRC_ADDR
        ld hl,$1748
        call _SET_MM_NUM_BYTES
        call _create_string
        ld a,b
        ld h,d
        ld l,e
        push af
        push hl
        call _inc2_ptr_ahl
        call _SET_ABS_DEST_ADDR
        call _mm_ldir

        pop hl
        pop af
        call _conv_addr         ;we've got to find this later
        or $40
        ld (savedatapage),a
        ld (savedatahl),hl
;find program
        ld hl,progname-1
        rst 20h
        rst 10h
        ld a,b
        ld h,d
        ld l,e
        call _conv_addr

        or $40
        out ($05),a             ;load it to rom slot
        res 7,h
        set 6,h                 ;fixup hl to point to the right place
        ld a,$41
        out ($06),a             ;load ram page 1

        ld e,(hl)
        inc hl
        ld d,(hl)
        inc hl
        inc hl
        inc hl
        ld a,$77
        cp d
        jr c,toobig             ;more than 30k

        push hl
        push de

;move callcode into place
        ld hl,callcode
        ld de,$f800
        ld bc,codesize
        ldir

        pop bc
        pop hl
        ld de,$8000
        jp callcode+callfixup   ;=$f800

toobig: ld hl,savedata-1
        rst 20h
        rst 10h
        call _delvar

        jp _memory_error

progname: .db 8,"bigprog1"

callfixup = $f800-$
callcode:
        call copydata+callfixup
        ld a,$d                 ;load rom page $d
        out ($05),a
        call $8000              ;run program
        ld a,(savedatapage+callfixup)
        out ($05),a             ;load save data
        ld hl,(savedatahl+callfixup)
        ld de,$c000
        ld bc,$1748             ;restore page 0 info
        call copydata
        ld a,$0d                ;load rom page $d
        out ($05),a
        ld hl,savedata-1        ;delete temp var
        rst 20h
        rst 10h
;        call _delvar
        ret

savedata: .db 8,1,"bigprog"
savedatapage: .db 0
savedatahl: .dw 0

;hl=from (can span pages)
;de=to
;bc=size
copydata:
        push hl
        push de
        ld de,$8000             ;has to be in rom slot
        or a
        sbc hl,de               ;get space left on page
        push hl
        sbc hl,bc               ;space on page-total
        jr c,extrabig           ;->it's bigger than that
        pop hl
        pop de                  ;strait copy
        pop hl
        ldir
        ret

extrabig:
        ;hl=space on page-total
        ld de,1                 ;carry is set
        ex de,hl
        sbc hl,de               ;get extra space
        pop bc
        pop de
        ex (sp),hl              ;save extra space
        ldir                    ;copy first page bit
        pop bc                  ;hl=extra space (left over)
        in a,($05)
        inc a
        out ($05),a             ;go to next page
        ld hl,$4000             ;start at beginning of page
        jr copydata

codesize = $-callcode

.end





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References:
Re: A86: can one program be on two pages?
From: TGaArdvark@aol.com