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;--------------------------------------------------------------------------
; __gptrget.s - read from pointer
;
; Copyright (c) 2019, Philipp Klaus Krause
;
; This library is free software; you can redistribute it and/or modify it
; under the terms of the GNU General Public License as published by the
; Free Software Foundation; either version 2, or (at your option) any
; later version.
;
; This library is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this library; see the file COPYING. If not, write to the
; Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
; MA 02110-1301, USA.
;
; As a special exception, if you link this library with other files,
; some of which are compiled with SDCC, to produce an executable,
; this library does not by itself cause the resulting executable to
; be covered by the GNU General Public License. This exception does
; not however invalidate any other reasons why the executable file
; might be covered by the GNU General Public License.
;--------------------------------------------------------------------------
.module __gptrget2
.area CODE
__gptrget2::
sub a, #0x80
t1sn f, c
goto code
; Pointer to RAM
idxm a, p
push af
inc p
idxm a, p
mov p, a
pop af
ret
; Pointer to ROM
code:
xch a, p
push af ; Put lower byte of pointer to first byte of value on stack.
call code2 ; Put return value for the ret at second byte of value on stack.
mov p, a
; Jump to lower byte. ret there will return from the call to __gptrget2
ret
code2:
add a, #1
push af ; Put lower byte of pointer to second byte of value on stack.
mov a, sp
add a, #-5
xch a, p
idxm p, a ; Put upper byte of pointer to first byte of value on stack.
pop af
push af
idxm a, p
addc a
xch a, p
add a, #4
xch a, p
idxm p, a ; Put lower byte of pointer to second byte of value on stack.
; Jump to upper byte. ret there will return from the call to code2
ret
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