/*-------------------------------------------------------------------------
_gptrget.c - get value for a generic pointer
Copyright (c) 1999, Sandeep Dutta . sandeep.dutta@usa.net
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.
-------------------------------------------------------------------------*/
/* not all devices use P2 to page pdata memory, therefore __XPAGE was
introduced. On some targets __XPAGE itself is a paged SFR so it is
not safe for all platforms to set this. Furthermore some targets
can be configured to behave differently for movx @dptr vs. movx @Ri
(don't drive high byte of address bus for movx @Ri only) */
#define USE_PDATA_PAGING_REGISTER 0
__sbit __at (0xF7) B_7;
__sbit __at (0xF6) B_6;
__sbit __at (0xF5) B_5;
/* the return value is expected to be in acc, and not in the standard
* location dpl. Therefore we choose return type void here: */
#if defined DSDCC_MODEL_HUGE
void
_gptrget (char *gptr) __naked
{
/* This is the banked version with pointers up to 23 bits.
B cannot be trashed */
gptr; /* hush the compiler */
__asm
;
; depending on the pointer type acc. to SDCCsymt.h
;
jb _B_7,codeptr$ ; >0x80 code ; 3
jnb _B_6,xdataptr$ ; <0x40 far ; 3
mov dph,r0 ; save r0 independant of regbank ; 2
mov r0,dpl ; use only low order address ; 2
jb _B_5,pdataptr$ ; >0x60 pdata ; 3
;
; Pointer to data space
;
mov a,@r0 ; 1
dataptrrestore$:
mov r0,dph ; restore r0 ; 2
mov dph,#0 ; restore dph ; 2
ret ; 1
;
; pointer to external stack or pdata
;
pdataptr$:
movx a,@r0 ; 1
sjmp dataptrrestore$ ; 2
;
; pointer to code area
;
codeptr$:
; implementation for SiLabs C8051F12x
mov a,b ; 2
anl a,#0x03 ; 2
swap a ; 1
push _PSBANK ; 2
anl _PSBANK,#0x0F ; 3
orl _PSBANK,a ; 2
clr a ; 1
movc a,@a+dptr ; 1
pop _PSBANK ; 2
ret ; 1
;
; pointer to xternal data
;
xdataptr$:
; implementation for xram a16-a21 tied to P3
mov _P3,b ; 3
movx a,@dptr ; 1
ret ; 1
;===
;44 bytes
__endasm;
}
#elif defined DSDCC_MODEL_MEDIUM
void
_gptrget (char *gptr) __naked
{
/* This is the non-banked version with pointers up to 15 bits.
Assumes B is free to be used */
gptr; /* hush the compiler */
__asm
;
; depending on the pointer type acc. to SDCCsymt.h
;
mov b,dph ; 3
jb _B_7,codeptr$ ; >0x80 code ; 3
jnb _B_6,xdataptr$ ; <0x40 far ; 3
mov b,r0 ; save r0 independant of regbank ; 2
mov r0,dpl ; use only low order address ; 2
jb _B_5,pdataptr$ ; >0x60 pdata ; 3
;
; Pointer to data space
;
mov a,@r0 ; 1
mov r0,b ; restore r0 ; 2
ret ; 1
;
; pointer to xternal stack or pdata
;
pdataptr$:
movx a,@r0 ; 1
mov r0,b ; restore r0 ; 2
ret ; 1
;
; pointer to code area, max 15 bits
;
codeptr$:
; 0x8000 <= dptr <= 0xFFFF
; no need to AND dph and restore from B if hardware wraps code memory
anl dph,#0x7F ; 3
clr a ; 1
movc a,@a+dptr ; 1
mov dph,b ; 3
ret ; 1
;
; pointer to xternal data, max 14 bits
;
xdataptr$:
; 0 <= dptr <= 0x3FFF
movx a,@dptr ; 1
ret ; 1
;===
;35 bytes
__endasm;
}
#else
void
_gptrget (char *gptr) __naked
{
/* This is the new version with pointers up to 16 bits.
B cannot be trashed */
gptr; /* hush the compiler */
__asm
;
; depending on the pointer type acc. to SDCCsymt.h
;
jb _B_7,codeptr$ ; >0x80 code ; 3
jnb _B_6,xdataptr$ ; <0x40 far ; 3
mov dph,r0 ; save r0 independant of regbank ; 2
mov r0,dpl ; use only low order address ; 2
jb _B_5,pdataptr$ ; >0x60 pdata ; 3
;
; Pointer to data space
;
mov a,@r0 ; 1
dataptrrestore$:
mov r0,dph ; restore r0 ; 2
mov dph,#0 ; restore dph ; 2
ret ; 1
;
; pointer to xternal stack or pdata
;
pdataptr$:
movx a,@r0 ; 1
sjmp dataptrrestore$ ; 2
;
; pointer to code area, max 16 bits
;
codeptr$:
clr a ; 1
movc a,@a+dptr ; 1
ret ; 1
;
; pointer to xternal data, max 16 bits
;
xdataptr$:
movx a,@dptr ; 1
ret ; 1
;===
;27 bytes
__endasm;
}
#endif
#ifdef __SDCC_ds390
/* the return value is expected to be in acc/acc1, and not in the standard
* location dpl/dph. Therefore we choose return type void here: */
void
_gptrgetWord (unsigned *gptr)
{
gptr; /* hush the compiler */
__asm
;
; depending on the pointer type acc. to SDCCsymt.h
;
jb _B_7,00003$ ; >0x80 code
jnb _B_6,00002$ ; <0x40 far
mov dph,r0 ; save r0 independant of regbank
mov r0,dpl ; use only low order address
jb _B_5,00004$ ; >0x60 pdata
;
; Pointer to data space
;
mov acc1,@r0
inc r0
mov a,@r0
inc dpl
sjmp 00005$
;
; pointer to xternal data
;
00002$:
movx a,@dptr
mov acc1,a
inc dptr
movx a,@dptr
sjmp 00006$
;
; pointer to code area
;
00003$:
clr a
movc a,@a+dptr
mov acc1,a
clr a
inc dptr
movc a,@a+dptr
sjmp 00006$
;
; pointer to xternal stack
;
00004$:
movx a,@r0
mov acc1,a
inc r0
movx a,@r0
inc dpl
;
; restore and return
;
00005$:
mov r0,dph ; restore r0
mov dph,#0 ; restore dph
00006$:
xch a,acc1
__endasm;
}
#endif