GCC Assembler Modifiers

[Andrew Haley]

Mohamed Bamakhrama writes:
 > Thanks Andrew.
 > One more question, where do I find those .md files? I searched for
 > them but I couldn't find them in my GCC installation directory.

Please don't top-post.

They're in the gcc source, in gcc/config/i386/

Andrew.

 > On 6/14/07, Andrew Haley <aph-gcc@littlepinkcloud.com> wrote:
 > > Mohamed Bamakhrama writes:
 > >
 > >  > I have two questions related to the modifiers that can be used with
 > >  > operands in inline assembly.
 > >  > 1) What does the 'z' mean when added to the operand modifier (e.g. %z0)?
 > >
 > > From i386.md:
 > >
 > > ;; The special asm out single letter directives following a '%' are:
 > > ;; 'z' mov%z1 would be movl, movw, or movb depending on the mode of
 > > ;;     operands[1].
 > > ;; 'L' Print the opcode suffix for a 32-bit integer opcode.
 > > ;; 'W' Print the opcode suffix for a 16-bit integer opcode.
 > > ;; 'B' Print the opcode suffix for an 8-bit integer opcode.
 > > ;; 'Q' Print the opcode suffix for a 64-bit float opcode.
 > > ;; 'S' Print the opcode suffix for a 32-bit float opcode.
 > > ;; 'T' Print the opcode suffix for an 80-bit extended real XFmode float opcode.
 > > ;; 'J' Print the appropriate jump operand.
 > > ;;
 > >
 > >  > 2) In the Input operands list, what is the meaning of 'J' (e.g. ... :
 > >  > .... : "Jr" (0) )?
 > >
 > > See 14.8, Register Classes, in the gcc internals manual.
 > >
 > > The machine-dependent operand constraint letters (`I', `J', `K',
 > > ... `P') specify particular ranges of integer values.
 > >
 > > Also, see constraints.md:
 > >
 > > (define_constraint "J"
 > >   "Integer constant in the range 0 ... 63, for 64-bit shifts."
 > >   (and (match_code "const_int")
 > >        (match_test "IN_RANGE (ival, 0, 63)")))
 > >
 > > Andrew.