[SOLVED] Inline assembly syntax error..
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Thanks for the comment. I tried a same example code segment from that page.
void toggleLed(unsigned char ledMask)
{
__asm {
mov al, 2
mov dx, 0xD007
out dx, al
}
}Once I compile the code it gives the following error. It wired to me from what the documentations explain (the link you gave, book I refer, etc..)
Error [192] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 39.1 undefined identifier "__asm"
Error [312] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 39.7 ";" expected
Error [285] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 no identifier in declaration
Warning [374] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 missing basic type; int assumed
Error [314] D:\Profiles\OC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 ";" expectedI appreciate your help all the time... CodingLover :)
I reread your original message and it seems you are using MPLAB to build this code. I suggest you check the documentation for your compiler to find out exactly why it complains about this. Are you sure this compiler supports the
__asmorasmkeywords? You may also be better using the MPLAB forum to get an answer to your question.Unrequited desire is character building. OriginalGriff I'm sitting here giving you a standing ovation - Len Goodman
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I just tried a search for P2LTCH with google, finding the following block of code here.
/**********************************************************************
*
* Function: toggleLed()
*
* Description: Toggle the state of one or both LED's.
*
* Notes: This function is specific to Arcom's Target188EB board.
*
* Returns: None defined.
*
**********************************************************************/
void
toggleLed(unsigned char ledMask)
{
#define P2LTCH 0xFF5E /* The address of the I/O register. */asm { mov dx, P2LTCH /\* Load the address of the register. \*/ in al, dx /\* Read the contents of the register. \*/ mov ah, ledMask /\* Move the ledMask into a register. \*/ xor al, ah /\* Toggle the requested bits. \*/ out dx, al /\* Write the new register contents. \*/ };} /* toggleLed() */
Reading through this, I thought of your asm statement - In the code you showed using round braces, you used the
asmkeyword. Later you showed some code with curly braces, however I see that in the seconds code snippet you have used the__asmkeyword, instead. If you haven't already, I'd try the syntax used in the above snippet. I've a very hazy memory that somewhere I read that the __asm keyword is a MS thing. Dunno, too lazy to check. :D Though I do note that in Code::Blocks,asmgets syntax-highlighted, while__asmdoesn't..Actually that is the same I am referring, O'Reillys' book. But it doesn't work for me. Seems to me that my compiler is not support this.
I appreciate your help all the time... CodingLover :)
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I reread your original message and it seems you are using MPLAB to build this code. I suggest you check the documentation for your compiler to find out exactly why it complains about this. Are you sure this compiler supports the
__asmorasmkeywords? You may also be better using the MPLAB forum to get an answer to your question.Unrequited desire is character building. OriginalGriff I'm sitting here giving you a standing ovation - Len Goodman
Yeah, seems to me that the compiler I am using with the MPLAB is not supporting the syntax. I am searching on the documentation at the min.
I appreciate your help all the time... CodingLover :)
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Thanks for the comment. I tried a same example code segment from that page.
void toggleLed(unsigned char ledMask)
{
__asm {
mov al, 2
mov dx, 0xD007
out dx, al
}
}Once I compile the code it gives the following error. It wired to me from what the documentations explain (the link you gave, book I refer, etc..)
Error [192] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 39.1 undefined identifier "__asm"
Error [312] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 39.7 ";" expected
Error [285] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 no identifier in declaration
Warning [374] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 missing basic type; int assumed
Error [314] D:\Profiles\OC\WorkOnProjects\PIC\Demo\led_blink.c; 44.1 ";" expectedI appreciate your help all the time... CodingLover :)
You need to terminate the __asm block with a ';' e.g. __asm { mov eax,0 mov ebx,10 }; Also note that you MUST preserve (push/pop) any registers you use within an __asm block. Another thing to note when using 'out' instruction - you may trigger an exception because the Windows OS allows only a few 'out' addresses accesses directly like that from user mode programs (ring 3). If I remember correctly only tho old LPT ports are accessible.
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You need to terminate the __asm block with a ';' e.g. __asm { mov eax,0 mov ebx,10 }; Also note that you MUST preserve (push/pop) any registers you use within an __asm block. Another thing to note when using 'out' instruction - you may trigger an exception because the Windows OS allows only a few 'out' addresses accesses directly like that from user mode programs (ring 3). If I remember correctly only tho old LPT ports are accessible.
I tried the same too, but no luck.
Snorri wrote:
Another thing to note when using 'out' instruction - you may trigger an exception because the Windows OS allows only a few 'out' addresses accesses directly like that from user mode programs (ring 3).
I don't have a big picture about this in my mind, since I am new to embedded systems yet. However, that information could be a value added. Thanks a lot.
I appreciate your help all the time... CodingLover :)
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Actually that is the same I am referring, O'Reillys' book. But it doesn't work for me. Seems to me that my compiler is not support this.
I appreciate your help all the time... CodingLover :)
Woooooah! Hold on just a minute. Did you say you're trying this code in mplab? That code is obviously x86 inline assembly, yet I though MPLab was for embedded devices - i.e mainly PICs. Looking at your compile log, it seems remarkably similar to the exerpt I just gotfor the HiTech C compiler, as shown below: Executing: "C:\Program Files (x86)\HI-TECH Software\PICC\9.80\bin\picc.exe" --pass1 C:\Users\enhzflep\Documents\mplab\proj1\..\main.c -q --chip=16F84A -P --runtime=default --opt=default -D__DEBUG=1 -g --asmlist "--errformat=Error [%n] %f; %l.%c %s" "--msgformat=Advisory[%n] %s" "--warnformat=Warning [%n] %f; %l.%c %s" Error [317] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 5.5 "(" expected Error [318] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 5.5 string expected Error [194] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 5.5 ")" expected Error [312] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 5.5 ";" expected Error [285] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 15.1 no identifier in declaration Warning [374] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 15.1 missing basic type; int assumed Error [314] C:\Users\enhzflep\Documents\mplab\proj1\..\main.c; 15.1 ";" expected ********** Build failed! ********** In that case, I think the problem is something else - i.e No, this compiler (a) won't accept the asm keyword (but you can easily make functions in asm files then link them together into your program) and more importantly (just now) (b) won't build programs that you can run on your PC - I'd have expected to see the code snippet in concern built using VS or GCC. Though, perhaps I'm just missing something?
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I just tried a search for P2LTCH with google, finding the following block of code here.
/**********************************************************************
*
* Function: toggleLed()
*
* Description: Toggle the state of one or both LED's.
*
* Notes: This function is specific to Arcom's Target188EB board.
*
* Returns: None defined.
*
**********************************************************************/
void
toggleLed(unsigned char ledMask)
{
#define P2LTCH 0xFF5E /* The address of the I/O register. */asm { mov dx, P2LTCH /\* Load the address of the register. \*/ in al, dx /\* Read the contents of the register. \*/ mov ah, ledMask /\* Move the ledMask into a register. \*/ xor al, ah /\* Toggle the requested bits. \*/ out dx, al /\* Write the new register contents. \*/ };} /* toggleLed() */
Reading through this, I thought of your asm statement - In the code you showed using round braces, you used the
asmkeyword. Later you showed some code with curly braces, however I see that in the seconds code snippet you have used the__asmkeyword, instead. If you haven't already, I'd try the syntax used in the above snippet. I've a very hazy memory that somewhere I read that the __asm keyword is a MS thing. Dunno, too lazy to check. :D Though I do note that in Code::Blocks,asmgets syntax-highlighted, while__asmdoesn't..enhzflep wrote:
I've a very hazy memory that somewhere I read that the __asm keyword is a MS thing.
This is true (about the double underscore, not your memory). ;)
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous
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enhzflep wrote:
I've a very hazy memory that somewhere I read that the __asm keyword is a MS thing.
This is true (about the double underscore, not your memory). ;)
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous
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Hi all, I start to do a simple application to control the P2LTCH(to blink a LED). So the toggle function as follow,
void toggleLed(unsigned char ledMask)
{
asm
(
mov dx, P2LTCH /* Load the address of the register. */
//in al, dx /* Read the contents of the register. */
//mov ah, ledMask /* Move the ledMask into a register. */
//xor al, ah /* Toggle the requested bits. */
//out dx, al /* Write the new register contents. */
);
}However, it returns the following error.
Error [318] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 41.1 string expected
Error [194] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 41.1 ")" expected
Error [312] D:\Profiles\PC\WorkOnProjects\PIC\Demo\led_blink.c; 41.1 ";" expectedI do the coding on MPLAB IDE. Any comments really appreciate.
I appreciate your help all the time... CodingLover :)
I found the solution my self by referring the MPLAB documentation. Inline assembly need to be wrapped as follows.
#asm
// assembly code goes here
#endasmI appreciate your help all the time... CodingLover :)
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I found the solution my self by referring the MPLAB documentation. Inline assembly need to be wrapped as follows.
#asm
// assembly code goes here
#endasmI appreciate your help all the time... CodingLover :)
CodingLover wrote:
...by referring the MPLAB documentation.
Keep that under your hat. ;)
"One man's wage rise is another man's price increase." - Harold Wilson
"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons
"Show me a community that obeys the Ten Commandments and I'll show you a less crowded prison system." - Anonymous