Hi,Krish
Thank you so much for answering my questions detailedly!
I‘ve got it.Thus next time I'll check the <****.h> file to find out the
specific register name of machine in SDCC.
Now I really want to know what SDCC compile flow is.How a c code become to
be a assembly code,even the machine code?
What is the differences between SDCC and GCC?
2011/3/23 Krishnendu Chatterjee <krishnendu.chatter...@gmail.com>
> Hi Donald,
> I am trying to re-clarify the concept of __sfr and __sbit.
>
> The statement '__sfr __at 0x9A MY_SFR' means that a new SFR is
> declared at 0x9A which is identified by the name MY_SFR in this
> program.
>
> However, this does not mean that MY_SFR.0 or MY_SFR_0 can be used to
> access the 'bit 0' of MY_SFR. To access that you need __sbit provided
> that location is bit-addressable. 0x9A is not a bit-addressable. So
> you cannot access the individual bits of this SFR.
>
> To define a bit-addressable register, the address must end with 0 or
> 8. Thus I can define a bit addressable register at 0xC0. But still
> then I have to define each bit of that SFR explicitly. Look at the
> following code:
>
> __sfr __at 0xC0 MY_BITADDRESSABLE_SFR;
> __sbit __at 0xC0 MY_BITADDRESSABLE_SFR_0;
> __sbit __at 0xC1 MY_BITADDRESSABLE_SFR_1;
> __sbit __at 0xC2 MY_BITADDRESSABLE_SFR_2;
> __sbit __at 0xC3 MY_BITADDRESSABLE_SFR_3;
> __sbit __at 0xC4 MY_BITADDRESSABLE_SFR_4;
> __sbit __at 0xC5 MY_BITADDRESSABLE_SFR_5;
> __sbit __at 0xC6 MY_BITADDRESSABLE_SFR_6;
> __sbit __at 0xC7 MY_BITADDRESSABLE_SFR_7;
>
> Sometime the individual bits are given special name. Then the above
> code changes to:
> __sfr __at 0xC0 MY_BITADDRESSABLE_SFR
> __sbit __at 0xC0 SPECIAL_0
> __sbit __at 0xC1 SPECIAL_1
> __sbit __at 0xC2 SPECIAL_2
> __sbit __at 0xC3 SPECIAL_3
> __sbit __at 0xC4 SPECIAL_4
> __sbit __at 0xC5 SPECIAL_5
> __sbit __at 0xC6 SPECIAL_6
> __sbit __at 0xC7 SPECIAL_7
>
> If you include <8051.h>, it already defines most of the SFR and SBIT
> of 8051 architecture. So that you don't have to re-write them.
>
> As far as PSW_1 is concerned, it has a special name called 'F1'. How
> do I know this? Well:
>
> 1) Search PSW in 8051.h. The statement looks like '__sfr __at (0xD0)
> PSW' which means it is at a location 0xD0.
> 2) Search of '__sbit __at (0xD0)' and find the following lines:
> __sbit __at (0xD0) P
> __sbit __at (0xD1) F1
> __sbit __at (0xD2) OV
> __sbit __at (0xD3) RS0
> __sbit __at (0xD4) RS1
> __sbit __at (0xD5) F0
> __sbit __at (0xD6) AC
> __sbit __at (0xD7) CY
> So now I know PSW_0 is called P, PSW_1 is called F1, PSW_2 is called
> OV and so on. So to set the 5-th bit of PSW, use RS1 = 1. not PSW_4 =
> 1.
>
>
> The sfr and sbit keywords are SDCC specific. So it is a good practice
> to add '__' (underscore underscore) prefix with them, just like other
> SDCC keywords, e.g. __bit, __data, __idata, __code, __xdata,
> __critical, __reentrant etc. Omitting this, new versions of sdcc
> generate deprecation warnings.
>
> Cheers.
> Krish
>
>
>
> On Wed, Mar 23, 2011 at 8:04 AM, duck donal <tangtao87657...@gmail.com>
> wrote:
> > Hi roelof,
> > Thanks for your help!
> > I run what you modify code in my pc,It can be compiled successfully!
> > However I have some questions to this code.
> > 1.What you use library files(p89lpc938.h) seems not the standard 51
> > library files.Does that mean I can subsitute this library for standard
> > 51 library?
> >
> > 2.You have no statements about P1_0/P1_7,Does that mean,the codes
> which
> > have been compiled with SDCC don't need the statements of sfr or sbit?
> > 3.I've tried another simple code(newpp.c) as what you told me,but the
> > sdcc give me such a error:newpp.c:error 20:Undefined identifier 'PSW_1'
> > the code as follow:
> > #include <AT89X51.H>
> > sfr f_wren=0xf1;
> > sfr f_pp=0xf2;
> > sfr f_wr_adrH=0xf3;
> > sfr f_wr_adrM=0xf4;
> > sfr f_wr_adrL=0xf5;
> > sfr f_wr_dataH=0xf6;
> > sfr f_wr_dataM1=0xf7;
> > sfr f_wr_dataM2=0xf8;
> > sfr f_wr_dataL=0xf9;
> > sfr f_rw=0xfa;
> > sfr f_work=0xfb;
> > main()
> > {
> >
> > f_wren=0x06;
> > f_pp=0x02;
> > f_wr_adrH=0x00;
> > f_wr_adrM=0x02;
> > f_wr_adrL=0x00;
> > f_wr_dataH=0x12;
> > f_wr_dataM1=0x34;
> > f_wr_dataM2=0x56;
> > f_wr_dataL=0x78;
> > f_rw=0x01;
> > f_work=0x01;
> > while(PSW_1==0)
> > f_work=0x00;
> > }o
> > I use PSW.1 instead of PSW_1,the SDCC give me a syntax error: token
> ->
> > '.1';column 11
> > So,what should be done on this code?
> > 4.I'm interesting in the SDCC compile internal,but manual is not
> very
> > detailed to the introduction of the internal
> > so,could u give me some material,such as SDCC compile
> flow,Whether
> > the SDCC have intermediate language,what is the difference between SDCC
> with
> > GCC
> >
> > Thanks!
> > Donald
> > 2011/3/22 roelof 't Hooft <roel...@itholland.nl>
> >>
> >> On Tue, 2011-03-22 at 10:02 +0800, duck donal wrote:
> >> > Hi All,
> >> > I'm a newbie for sdcc.
> >> > A few days ago, I was in use of SDCC, ran into a problem.
> >>
> >> > So,what is the solutions?To modify the program?How to do it?
> >> > Or modify the sdcc?
> >>
> >> Hi Donald,
> >>
> >> Here is your example code back, I modified it a bit to
> >> have it succesfully compile with sdcc.
> >> As opposed to arm-elf-gcc sdcc does not need or use the
> >> return at the end of a program, embedded programs usually
> >> never return and stay in a while(1) loop forever :-)
> >>
> >> #include <p89lpc938.h>
> >>
> >> void main(void)
> >> {
> >> unsigned char j;
> >> unsigned int i;
> >>
> >> while(1)
> >> {
> >> P1_7 = 1;
> >> while(P1_7 == 0)
> >> {
> >> for(i = 1; i <= 500; i++)
> >> {
> >> P1_0 = !P1_0;
> >> for(j = 0; j <= 50; j++)
> >> {
> >> }
> >> }
> >> for(i = 1; i <= 250; i++)
> >> {
> >> P1_0 = !P1_0;
> >> for(j = 0; j <= 100; j++)
> >> {
> >> }
> >> }
> >> }
> >> }
> >> }
> >>
> >> roelofh@baywatch:~/tangtao$ sdcc tang.c
> >> roelofh@baywatch:~/tangtao$ ll
> >> total 196
> >> -rw-r--r-- 1 roelofh domainusers 13302 2011-03-22 10:48 tang.asm
> >> -rw-r--r-- 1 roelofh domainusers 333 2011-03-22 10:48 tang.c
> >> -rw-r--r-- 1 roelofh domainusers 620 2011-03-22 10:48 tang.ihx
> >> -rw-r--r-- 1 roelofh domainusers 215 2011-03-22 10:48 tang.lnk
> >> -rw-r--r-- 1 roelofh domainusers 35446 2011-03-22 10:48 tang.lst
> >> -rw-r--r-- 1 roelofh domainusers 34876 2011-03-22 10:48 tang.map
> >> -rw-r--r-- 1 roelofh domainusers 1129 2011-03-22 10:48 tang.mem
> >> -rw-r--r-- 1 roelofh domainusers 6201 2011-03-22 10:48 tang.rel
> >> -rw-r--r-- 1 roelofh domainusers 35446 2011-03-22 10:48 tang.rst
> >> -rw-r--r-- 1 roelofh domainusers 47706 2011-03-22 10:48 tang.sym
> >> roelofh@baywatch:~/tangtao$ sdcc -v
> >> SDCC : mcs51 3.0.1 #6066 (23 Nov 2010) (Linux)
> >>
> >> You will find the header files in /usr/local/share/sdcc/include/mcs51/
> >> Please have a look at them and include the one you need for your
> >> processor. I have included a random one for example.
> >>
> >> roelof
> >>
> >>
> >>
> >>
> >>
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> >
> >
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