Re: [Sdcc-user] memory initialisation in xdata

[Ragnar S. <ra...@na...>]

"xdata" should work, since xdata memoru space is initialised with
generated code, see example 1 below.
I use "code" (for *my* ez-usb project with ported cypress EZUSB
framework :-) since it is much more compact - no code is generated,
just the data is layed out in the image. Just make even more sure
that you don't index beyond boundaries and such, since your data
will be surrounded by code, and a bug that accidentally changes
code might be really tricky to find.

------------------------------------------------

Example 1: xdata initialization (sdcc ~2.2.2, solaris):
c-code:
xdata char foo[] = {0x11, 0x22, 0x33, 0x44};

asm:
;--------------------------------------------------------
; external ram data
;--------------------------------------------------------
        .area XSEG    (XDATA)
G$foo$0$0==.
_foo::
        .ds 4
;--------------------------------------------------------
; global & static initialisations
;--------------------------------------------------------
        .area GSINIT  (CODE)
        .area GSFINAL (CODE)
        .area GSINIT  (CODE)
;       test2.c 3
        mov     dptr,#_foo
        mov     a,#0x11
        movx    @dptr,a
        mov     dptr,#(_foo + 0x0001)
        mov     a,#0x22
        movx    @dptr,a
        mov     dptr,#(_foo + 0x0002)
        mov     a,#0x33
        movx    @dptr,a
        mov     dptr,#(_foo + 0x0003)
        mov     a,#0x44
        movx    @dptr,a

------------------------------------------------

Example 2: code initialization

c-code:
xdata char foo[] = {0x11, 0x22, 0x33, 0x44};

asm:
;--------------------------------------------------------
; code
;--------------------------------------------------------
        .area CSEG    (CODE)
        .area CSEG    (CODE)
G$foo$0$0 == .
_foo:
        .db #0x11
        .db #0x22
        .db #0x33
        .db #0x44

------------------------------------------------

/ragge