mfcpusptrpcgetrxx/src/mfcpusptrpcgetrxx.s

;-------------------------------------------------------------------------------
;$Header: /home/dashley/cvsrep/uculib01/uculib01/src/stm8/cosmic/modx0/mfcpusptrpcgetrxx/src/mfcpusptrpcgetrxx.s,v 1.4 2010/03/21 04:50:34 dashley Exp $
;-------------------------------------------------------------------------------
;Copyright (c)2010 David T. Ashley
;
;Permission is hereby granted, free of charge, to any person obtaining a copy
;of this software source code and associated documentation files (the
;"Software"), to deal in the Software without restriction, including without
;limitation the rights to use, copy, modify, merge, publish, distribute,
;sublicense, and/or sell copies of the Software, and to permit persons to whom
;the Software is furnished to do so, subject to the following conditions:
;
;The above copyright notice and this permission notice shall be included in
;all copies or substantial portions of the Software.
;
;THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
;THE SOFTWARE.
;-------------------------------------------------------------------------------
;This function doesn't use any static storage, so it is OK for either mods0 or
;modsl0 memory models.  However, it does assume call/ret (rather than callf/retf)
;which affects both instructions used, stack offsets, and numerical values in
;the .dcall directive.  For this reason, must error out if being assembled
;for the wrong memory model.
#ifndef UCU_BD_MMBP
   #error "Program memory model define not provided on command line (UCU_BD_MMBP)."
#endif
#if (UCU_BD_MMBP != 1)
   #error "Attempt to assemble module for wrong program memory model (UCU_BD_MMBP != 1)."
#endif
;
            switch .text
            xdef   _UcuMfCpuSptrPcGetRxx
;
;Per discussion with Cosmic, the first integer is the stack space used by the
;call instruction plus any automatic storage used by the function.  The second integer
;is the number of bytes stacked by the caller.  Haven't yet discussed the scenario
;of one assembly-language function called by another.  I've noticed that some
;assembly-language functions have a larger first integer than the stack they
;used, so there may be a special convention if C calls .S which then calls .S,
;as maybe the tools don't detect the .S calling the .S.  Will need to investigate
;further with Cosmic.
;
;2 bytes stacked by the CALL instruction, 0 bytes stacked by the caller.
        .dcall  "2,0,_UcuMfCpuSptrPcGetRxx"
;
_UcuMfCpuSptrPcGetRxx:
        ldw   x,sp            ;Copy the stack pointer to x.
        addw  x,#2            ;The call caused the stack to grow towards lower memory addresses by 2.
                              ;This addition causes the stack pointer at the time of call to be
                              ;calculated.  The X register is the location of the return value.
        ret                   ;Return value set up.  Can return.
;
        end
;
;-------------------------------------------------------------------------------
;End of $Id: mfcpusptrpcgetrxx.s,v 1.4 2010/03/21 04:50:34 dashley Exp $
;-------------------------------------------------------------------------------
;$Log: mfcpusptrpcgetrxx.s,v $
;Revision 1.4  2010/03/21 04:50:34  dashley
;Comments corrected.
;
;Revision 1.3  2010/02/20 16:07:22  dashley
;Missing switch directive added.
;
;Revision 1.2  2010/02/14 03:26:04  dashley
;Extra line removed.
;
;Revision 1.1  2010/02/14 03:25:40  dashley
;Initial checkin.
;-------------------------------------------------------------------------------

1	;-------------------------------------------------------------------------------
2	;$Header: /home/dashley/cvsrep/uculib01/uculib01/src/stm8/cosmic/modx0/mfcpusptrpcgetrxx/src/mfcpusptrpcgetrxx.s,v 1.4 2010/03/21 04:50:34 dashley Exp $
3	;-------------------------------------------------------------------------------
4	;Copyright (c)2010 David T. Ashley
5	;
6	;Permission is hereby granted, free of charge, to any person obtaining a copy
7	;of this software source code and associated documentation files (the
8	;"Software"), to deal in the Software without restriction, including without
9	;limitation the rights to use, copy, modify, merge, publish, distribute,
10	;sublicense, and/or sell copies of the Software, and to permit persons to whom
11	;the Software is furnished to do so, subject to the following conditions:
12	;
13	;The above copyright notice and this permission notice shall be included in
14	;all copies or substantial portions of the Software.
15	;
16	;THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17	;IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18	;FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
19	;AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20	;LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21	;OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22	;THE SOFTWARE.
23	;-------------------------------------------------------------------------------
24	;This function doesn't use any static storage, so it is OK for either mods0 or
25	;modsl0 memory models. However, it does assume call/ret (rather than callf/retf)
26	;which affects both instructions used, stack offsets, and numerical values in
27	;the .dcall directive. For this reason, must error out if being assembled
28	;for the wrong memory model.
29	#ifndef UCU_BD_MMBP
30	#error "Program memory model define not provided on command line (UCU_BD_MMBP)."
31	#endif
32	#if (UCU_BD_MMBP != 1)
33	#error "Attempt to assemble module for wrong program memory model (UCU_BD_MMBP != 1)."
34	#endif
35	;
36	switch .text
37	xdef _UcuMfCpuSptrPcGetRxx
38	;
39	;Per discussion with Cosmic, the first integer is the stack space used by the
40	;call instruction plus any automatic storage used by the function. The second integer
41	;is the number of bytes stacked by the caller. Haven't yet discussed the scenario
42	;of one assembly-language function called by another. I've noticed that some
43	;assembly-language functions have a larger first integer than the stack they
44	;used, so there may be a special convention if C calls .S which then calls .S,
45	;as maybe the tools don't detect the .S calling the .S. Will need to investigate
46	;further with Cosmic.
47	;
48	;2 bytes stacked by the CALL instruction, 0 bytes stacked by the caller.
49	.dcall "2,0,_UcuMfCpuSptrPcGetRxx"
50	;
51	_UcuMfCpuSptrPcGetRxx:
52	ldw x,sp ;Copy the stack pointer to x.
53	addw x,#2 ;The call caused the stack to grow towards lower memory addresses by 2.
54	;This addition causes the stack pointer at the time of call to be
55	;calculated. The X register is the location of the return value.
56	ret ;Return value set up. Can return.
57	;
58	end
59	;
60	;-------------------------------------------------------------------------------
61	;End of $Id: mfcpusptrpcgetrxx.s,v 1.4 2010/03/21 04:50:34 dashley Exp $
62	;-------------------------------------------------------------------------------
63	;$Log: mfcpusptrpcgetrxx.s,v $
64	;Revision 1.4 2010/03/21 04:50:34 dashley
65	;Comments corrected.
66	;
67	;Revision 1.3 2010/02/20 16:07:22 dashley
68	;Missing switch directive added.
69	;
70	;Revision 1.2 2010/02/14 03:26:04 dashley
71	;Extra line removed.
72	;
73	;Revision 1.1 2010/02/14 03:25:40 dashley
74	;Initial checkin.
75	;-------------------------------------------------------------------------------
76