I just finish ,all working as expected I guess, my first assembler application using free Yar Software , on MSP430F1232; a simple(1,4k code) controller for a diving lamp. I used OLIMEX hardware prototype and works very well. The problems I face durig develop where often bad usage of assembler syntax. I fact I did not find a clear explanation of the rules , for example the special character, like # , & , define. What I learn is: # need to be place in front at numbers like : MOV.B #001F,R6 & seems need in front on periferal register like: mov.b #000h,&P1OUT define. definition of a memory location. for example : define memory1 (0x00200) define memory2 (0x00201) ====================One mistake was define a number to be used in program as a constant numeric value instead write the number itself to make more readable the program ,ie: define LAMP_MAX_POWER (0x00F) mov.b LAMP_MAX_POWER, LAMP_power_memory_location How is possible something as above. =======================Another think not clear, with following command CMP.B Mem_loc1,Mem_loc2 I compare the memory location address or the content, I think the content. In summary , are there someone in this community that have a piece of paper where all above simpler assembler rules and syntax are explained. I read apps note SLAU49C but I still have these doubt in mind (may be I'm stipud). Thanks for help. Paolo. --------------------------------- Yahoo! Mail: 6MB di spazio gratuito, 30MB per i tuoi allegati, l'antivirus, il filtro Anti-spam
Info on assembler syntax
Started by ●September 13, 2003
Reply by ●September 14, 20032003-09-14
Paulo, you're obviously not stupid if you got it to work! The syntax
is
confusing, and to undertsand it I recommend you read SLAUE10B, chapters
5 and 9 IIRC, plus have a good read of SLAA024, the applications
reports. Chapters 6,7 & 8 contain some useful pointers on both hardware
and software.
basically # indicates an absolute value, which includes the address for
a CALL, or BR instruction, since BR is actually a direct modification of
the PC, BR #DAVE is actually translated into MOV #DAVE,PC.
& inndicates absolute mode, where the value after & is the actual
address or value. So MOV &DAVE,&FRED means move data at address DAVE to
address FRED.
No prefix means what Ti call symbolic mode, this is similar to absolute,
and sometimes interchangable, but not always.
MOV DAVE,FRED translates to MOV DAVE(PC),FRED(PC).
Hence
&P1OUT refers to the data at the adress P1OUT
#p1OUT is the actual address of the P1OUT register
P1OUT depends a little upon how you declared P1OUT, but, in most cases
will likely be the same as &P1OUT.
Al
Giampaolo Consonni wrote:
> I just finish ,all working as expected I guess, my
first assembler application using free Yar Software , on MSP430F1232; a
simple(1,4k code) controller for a diving lamp.
> I used OLIMEX hardware prototype and works very well.
>
> The problems I face durig develop where often bad usage of assembler
syntax. I fact I did not find a clear explanation of the rules , for example
the special character, like # , & , define.
>
> What I learn is:
> # need to be place in front at numbers like : MOV.B #001F,R6
> & seems need in front on periferal register like: mov.b
#000h,&P1OUT
> define. definition of a memory location.
>
> for example :
> define memory1 (0x00200)
> define memory2 (0x00201)
> ====================> One mistake was define a number to be used in
program as a constant numeric value instead write the number itself to make
more readable the program ,ie:
> define LAMP_MAX_POWER (0x00F)
>
> mov.b LAMP_MAX_POWER, LAMP_power_memory_location
>
> How is possible something as above.
> =======================> Another think not clear, with following command
>
> CMP.B Mem_loc1,Mem_loc2
> I compare the memory location address or the content, I think the content.
>
> In summary , are there someone in this community that have a piece of paper
where all above simpler assembler rules and syntax are explained.
> I read apps note SLAU49C but I still have these doubt in mind (may be
I'm stipud).
>
> Thanks for help. Paolo.
>
>
>
>
>
>
>
> ---------------------------------
> Yahoo! Mail: 6MB di spazio gratuito, 30MB per i tuoi allegati,
l'antivirus, il filtro Anti-spam
>
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●September 14, 20032003-09-14
Is like when we buy a new "electronics toy", we start play with,
before
read all user instruction.
I normally read user instructions, but in this case are very deep into
documentation. I saw examples into slaa24 of wath i need i try to used
but error messages again.Then I remember some notes regarding differencies
between TI and Yar mnemonics.
Finally the Yar manual "MPS430 assembler,linker and librarian Programming
Giude" is wath I was looking for.
Thanks onestone
onestone <onestone@ones...> wrote:
Paulo, you're obviously not stupid if you got it to work! The syntax is
confusing, and to undertsand it I recommend you read SLAUE10B, chapters
5 and 9 IIRC, plus have a good read of SLAA024, the applications
reports. Chapters 6,7 & 8 contain some useful pointers on both hardware
and software.
basically # indicates an absolute value, which includes the address for
a CALL, or BR instruction, since BR is actually a direct modification of
the PC, BR #DAVE is actually translated into MOV #DAVE,PC.
& inndicates absolute mode, where the value after & is the actual
address or value. So MOV &DAVE,&FRED means move data at address DAVE to
address FRED.
No prefix means what Ti call symbolic mode, this is similar to absolute,
and sometimes interchangable, but not always.
MOV DAVE,FRED translates to MOV DAVE(PC),FRED(PC).
Hence
&P1OUT refers to the data at the adress P1OUT
#p1OUT is the actual address of the P1OUT register
P1OUT depends a little upon how you declared P1OUT, but, in most
cases
will likely be the same as &P1OUT.
Al
Giampaolo Consonni wrote:
> I just finish ,all working as expected I guess, my
first assembler application using free Yar Software , on MSP430F1232; a
simple(1,4k code) controller for a diving lamp.
> I used OLIMEX hardware prototype and works very well.
>
> The problems I face durig develop where often bad usage of assembler
syntax. I fact I did not find a clear explanation of the rules , for example
the special character, like # , & , define.
>
> What I learn is:
> # need to be place in front at numbers like : MOV.B #001F,R6
> & seems need in front on periferal register like: mov.b
#000h,&P1OUT
> define. definition of a memory location.
>
> for example :
> define memory1 (0x00200)
> define memory2 (0x00201)
> ====================> One mistake was define a number to be used in
program as a constant numeric value instead write the number itself to make
more readable the program ,ie:
> define LAMP_MAX_POWER (0x00F)
>
> mov.b LAMP_MAX_POWER, LAMP_power_memory_location
>
> How is possible something as above.
> =======================> Another think not clear, with following command
>
> CMP.B Mem_loc1,Mem_loc2
> I compare the memory location address or the content, I think the content.
>
> In summary , are there someone in this community that have a piece of paper
where all above simpler assembler rules and syntax are explained.
> I read apps note SLAU49C but I still have these doubt in mind (may be
I'm stipud).
>
> Thanks for help. Paolo.
>
>
>
>
>
>
>
> ---------------------------------
> Yahoo! Mail: 6MB di spazio gratuito, 30MB per i tuoi allegati,
l'antivirus, il filtro Anti-spam
>
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
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var link="javascript:LRECopenWindow(1)"; var lrec_flashfile =
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Reply by ●September 14, 20032003-09-14
Giampaolo: I think the things you mentioned are really confusing too! > define LAMP_MAX_POWER (0x00F) > mov.b LAMP_MAX_POWER, LAMP_power_memory_location > How is possible something as above. You would need to write: mov.b #LAMP_MAX_POWER,LAMP_power_memory_location > Another think not clear, with following command > CMP.B Mem_loc1,Mem_loc2 > I compare the memory location address or the content, I think > the content. Yes. My understanding so far is if you're using simple equates to define labels it ends up being generally: # says the label is a literal (just a number). You place it in front of a symbol which represents a number but and also in front of a number. Without it is assumed to be an address reference. Except in the case of Call where you would need it when referring to section and sub labels. & for fixed addresses like peripheral registers. Leave it off when letting the assembler decide what the actual address is (tables, etc). A comparison of the two modes you mentioned might be: PowerUp cmp.b #LAMP_MAX_POWER,last_power_level jlo Restore jne Default Restore mov.b last_power_level,Rpass1 jmp DonePU Default mov.b DefaultBrightness,Rpass1 DonePU call #SetLevel ....... Brighten cmp.b #LAMP_MAX_POWER,current_power_level jeq Done mov.b current_power_level,last_power_level incr.b current_power_level mov.b current_power_level,Rass1 call #SetLevel Done ....... ret etc. > I read apps note SLAU49C but I still have these doubt in mind > (may be I'm stipud). No, unless we both are ;) I find the TI documentation very confusing. I've still got a lot to learn and it's slow going. I spend an awful lot of time reading the addressing modes description and the instruction set summary, over and over again, while programming. It's a lot easier to just program in C, but I'm stubborn and I need to really understand this. Beyond studying example programs, another way I get some clues about syntax is to study the assembly output of the compiler (even if you want to program in assembly you could write code fragments in C periodically to see exactly how the syntax is applied to a generate a particular outcome). I'm waiting for an in-depth primer on the instruction set, especially addressing modes, with complete explanations of where, why and how each is used, and where they are used differently with different instructions, and why, and many well-explained examples. --Bruce
Reply by ●September 14, 20032003-09-14
Bruce Cannon wrote: > Giampaolo: > > I think the things you mentioned are really confusing too! > > >>define LAMP_MAX_POWER (0x00F) >>mov.b LAMP_MAX_POWER, LAMP_power_memory_location >>How is possible something as above. > > > You would need to write: > > mov.b #LAMP_MAX_POWER,LAMP_power_memory_location > > > >>Another think not clear, with following command >>CMP.B Mem_loc1,Mem_loc2 >>I compare the memory location address or the content, I think >>the content. > > > Yes. My understanding so far is if you're using simple equates to define > labels it ends up being generally: # says the label is a literal (just a > number). You place it in front of a symbol which represents a number but > and also in front of a number. Without it is assumed to be an address > reference. Except in the case of Call where you would need it when > referring to section and sub labels. & for fixed addresses like peripheral > registers. Leave it off when letting the assembler decide what the actual > address is (tables, etc). > > A comparison of the two modes you mentioned might be: > > PowerUp cmp.b #LAMP_MAX_POWER,last_power_level > jlo Restore > jne Default > Restore mov.b last_power_level,Rpass1 > jmp DonePU > Default mov.b DefaultBrightness,Rpass1 > DonePU call #SetLevel > ....... > > Brighten cmp.b #LAMP_MAX_POWER,current_power_level > jeq Done > mov.b current_power_level,last_power_level > incr.b current_power_level > mov.b current_power_level,Rass1 > call #SetLevel > Done ....... > ret > > etc. > > > >>I read apps note SLAU49C but I still have these doubt in mind >>(may be I'm stipud). > > > No, unless we both are ;) I find the TI documentation very confusing. > I've still got a lot to learn and it's slow going. I spend an awful lot of > time reading the addressing modes description and the instruction set > summary, over and over again, while programming. It's a lot easier to just > program in C, but I'm stubborn and I need to really understand this. Ti's documentation is quite clear. It's just not all in one convenient place. It's scattered throughout several documents. Easier in C? After all the confusion that we seem to have here about in line assembler, how to fix the position of this or that, and especially those embedded C jewels where, of course ANSI C was not designed for embedded systems, so each compiler writer gets to decide what extras they put in, and how they handle the embedded worlds non-standard necessities. It doesn't even look right to me. ;@} > > Beyond studying example programs, another way I get some clues about syntax > is to study the assembly output of the compiler (even if you want to > program in assembly you could write code fragments in C periodically to see > exactly how the syntax is applied to a generate a particular outcome). > > I'm waiting for an in-depth primer on the instruction set, especially > addressing modes, with complete explanations of where, why and how each is > used, and where they are used differently with different instructions, and > why, and many well-explained examples. Doesn't the new book by Chris? Nagy cover that? Al
Reply by ●September 14, 20032003-09-14
Think of it as C. # means "The immediate number" or "the
address of". In
fact when used by the CALL instruction:-
CALL #DO_THIS
...
...
DO_THIS:
MOV R4,R5
RET
It means the literal value of DO_THIS, which is the address of the
label. If written:-
CALL DO_THIS
It means call the address contained at the label DO_THIS. No different
to C pointers really,
aL
Bruce Cannon wrote:
> Giampaolo:
>
> I think the things you mentioned are really confusing too!
>
>
>>define LAMP_MAX_POWER (0x00F)
>>mov.b LAMP_MAX_POWER, LAMP_power_memory_location
>>How is possible something as above.
>
>
> You would need to write:
>
> mov.b #LAMP_MAX_POWER,LAMP_power_memory_location
>
>
>
>>Another think not clear, with following command
>>CMP.B Mem_loc1,Mem_loc2
>>I compare the memory location address or the content, I think
>>the content.
>
>
> Yes. My understanding so far is if you're using simple equates to
define
> labels it ends up being generally: # says the label is a literal (just a
> number). You place it in front of a symbol which represents a number but
> and also in front of a number. Without it is assumed to be an address
> reference. Except in the case of Call where you would need it when
> referring to section and sub labels. & for fixed addresses like
peripheral
> registers. Leave it off when letting the assembler decide what the actual
> address is (tables, etc).
>
> A comparison of the two modes you mentioned might be:
>
> PowerUp cmp.b #LAMP_MAX_POWER,last_power_level
> jlo Restore
> jne Default
> Restore mov.b last_power_level,Rpass1
> jmp DonePU
> Default mov.b DefaultBrightness,Rpass1
> DonePU call #SetLevel
> .......
>
> Brighten cmp.b #LAMP_MAX_POWER,current_power_level
> jeq Done
> mov.b current_power_level,last_power_level
> incr.b current_power_level
> mov.b current_power_level,Rass1
> call #SetLevel
> Done .......
> ret
>
> etc.
>
>
>
>>I read apps note SLAU49C but I still have these doubt in mind
>>(may be I'm stipud).
>
>
> No, unless we both are ;) I find the TI documentation very confusing.
> I've still got a lot to learn and it's slow going. I spend an
awful lot of
> time reading the addressing modes description and the instruction set
> summary, over and over again, while programming. It's a lot easier to
just
> program in C, but I'm stubborn and I need to really understand this.
>
> Beyond studying example programs, another way I get some clues about syntax
> is to study the assembly output of the compiler (even if you want to
> program in assembly you could write code fragments in C periodically to see
> exactly how the syntax is applied to a generate a particular outcome).
>
> I'm waiting for an in-depth primer on the instruction set, especially
> addressing modes, with complete explanations of where, why and how each is
> used, and where they are used differently with different instructions, and
> why, and many well-explained examples.
>
> --Bruce
>
>
>
>
> .
>
>
>
> ">http://docs.yahoo.com/info/terms/
>
>
>
Reply by ●September 15, 20032003-09-15
Thanks Al!
I still don't get two things:
1. In you last comment about CALLing a label without '#', do you mean
that
DO_THIS is then understood to be a label for a number which is an address
to a memory location which in turn contains the address of the subroutine?
And also:
2. Why do we need to write
jmp DoThis
but
call #DoThis
to refer to the exact same address label?
--Bruce
> Think of it as C. # means "The immediate
number" or "the address of". In
> fact when used by the CALL instruction:-
>
> CALL #DO_THIS
> ...
> ...
> DO_THIS:
> MOV R4,R5
> RET
>
> It means the literal value of DO_THIS, which is the address of the
> label. If written:-
>
> CALL DO_THIS
>
> It means call the address contained at the label DO_THIS. No different
> to C pointers really,
>
> aL
Reply by ●September 15, 20032003-09-15
On Mon, Sep 15, 2003 at 11:39:10AM -0700, Bruce Cannon wrote: > 1. In you last comment about CALLing a label without '#', do you mean that > DO_THIS is then understood to be a label for a number which is an address Basically this means you are wanting an indirect call via the referenced variable as opposed to calling the function at the specified address. > 2. Why do we need to write > jmp DoThis > but > call #DoThis A good question - it's an inconsistency in the syntax - if I had designed it, I would have made call the same as jmp, and used something like call @fptr for indirect function calls. -- Clyde Stubbs | HI-TECH Software Email: clyde@clyd... | Phone Fax WWW: http://www.htsoft.com/ | USA: (408) 490 2885 (408) 490 2885 PGP: finger clyde@clyd... | AUS: +61 7 3552 7777 +61 7 3552 7778 --- HI-TECH C: compiling the real world.
Reply by ●September 15, 20032003-09-15
At 09:27 AM 9/16/2003 +1000, Clyde Stubbs wrote: >On Mon, Sep 15, 2003 at 11:39:10AM -0700, Bruce Cannon wrote: > > 1. In you last comment about CALLing a label without '#', do you mean that > > DO_THIS is then understood to be a label for a number which is an address > >Basically this means you are wanting an indirect call via the referenced >variable as opposed to calling the function at the specified address. > > > 2. Why do we need to write > > jmp DoThis > > but > > call #DoThis > >A good question - it's an inconsistency in the syntax - if I had designed it, >I would have made call the same as jmp, and used something like > > call @fptr > >for indirect function calls. >... IMHO, I think it's a mistake. This means you cannot have PC relative calls. Oh well, at least we are not fighting w/ the . (DOT) problem w/ BLISS!!! // richard <http://www.imagecraft.com> <http://www.dragonsgate.net/mailman/listinfo>
Reply by ●September 15, 20032003-09-15
