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GNU Info (gcc-295.info)AssemblerAssembler Instructions as Expressions ===================================== The RTX code `asm_operands' represents a value produced by a user-specified assembler instruction. It is used to represent an `asm' statement with arguments. An `asm' statement with a single output operand, like this: asm ("foo %1,%2,%0" : "=a" (outputvar) : "g" (x + y), "di" (*z)); is represented using a single `asm_operands' RTX which represents the value that is stored in `outputvar': (set RTX-FOR-OUTPUTVAR (asm_operands "foo %1,%2,%0" "a" 0 [RTX-FOR-ADDITION-RESULT RTX-FOR-*Z] [(asm_input:M1 "g") (asm_input:M2 "di")])) Here the operands of the `asm_operands' RTX are the assembler template string, the output-operand's constraint, the index-number of the output operand among the output operands specified, a vector of input operand RTX's, and a vector of input-operand modes and constraints. The mode M1 is the mode of the sum `x+y'; M2 is that of `*z'. When an `asm' statement has multiple output values, its insn has several such `set' RTX's inside of a `parallel'. Each `set' contains a `asm_operands'; all of these share the same assembler template and vectors, but each contains the constraint for the respective output operand. They are also distinguished by the output-operand index number, which is 0, 1, ... for successive output operands. automatically generated by info2www version 1.2.2.9 |