M68k Inline Assmbly with C Style Operands

M68k Inline Assmbly with C Style Operands

[Alex Holland]

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Hi,
 
Using gcc-2.95.2 cross development 
tools  for a m68k-elf target under Cygwin, I am having problems 
getting inline assembly with C operands to compile/assemble/link:
 
// Example 1: No C style operands  works 
fine.
asm("move  0x2700, %sr");  
 
// Example 2: The % in %sr made the compiler look for 
another operand. 
#define MY_MACRO 0x2700
 
asm("move  %0, %sr;"     : 
    : "i"(MY_MACRO) );
 
// Example 3: Would not link because sr is 
undefined.
asm("move  %0, sr;"     : 
    : "i"(MY_MACRO) );
Any suggestions for making Example 2 or Example 3 
work?
 
Thanks, Alex

M68k Inline Assmbly with C Style Operands

[Doug Evans]

Alex Holland writes:
 > // Example 1: No C style operands  works fine.
 > asm("move  0x2700, %sr");  

Without arguments, gcc passes the string through to the assembler
unchanged.  This is a DIFFERENT kind of asm than an asm with colon
separated arguments.  For example, such an asm is always marked as
"volatile" (IIRC!), and it can be used outside functions.

 > // Example 2: The % in %sr made the compiler look for another operand. 
 > #define MY_MACRO 0x2700
 > 
 > asm("move  %0, %sr;"
 >     : 
 >     : "i"(MY_MACRO)
 > );

s/%sr/%%sr/

 > // Example 3: Would not link because sr is undefined.
 > asm("move  %0, sr;"
 >     : 
 >     : "i"(MY_MACRO)
 > );

I'm guessing %%sr is what you want.

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