What is __ asm __ in C?

The __asm keyword invokes the inline assembler and can appear wherever a C or C++ statement is legal. It cannot appear by itself. It must be followed by an assembly instruction, a group of instructions enclosed in braces, or, at the very least, an empty pair of braces.

What does asm volatile mean?

Volatile is used to force it to read a fresh timestamp. When used alone, like this: __asm__ __volatile__ (“”) It will not actually execute anything. You can extend this, though, to get a compile-time memory barrier that won’t allow reordering any memory access instructions: __asm__ __volatile__ (“”:::”memory”)

What is PowerPC assembly?

PowerPC architecture is an example of a RISC (Reduced Instruction Set Computing) architecture. As a result: All PowerPCs (including 64-bit implementations) use fixed-length 32-bit instructions. The PowerPC processing model is to retrieve data from memory, manipulate it in registers, then store it back to memory.

Can a constraint be used with an ASM operand?

Here are specific details on what constraint letters you can use with asm operands. Constraints can say whether an operand may be in a register, and which kinds of register; whether the operand can be a memory reference, and which kinds of address; whether the operand may be an immediate constant, and which possible values it may have.

Are there any synonyms for the word constraints?

Synonyms for constraints include shackles, barriers, hindrances, impediments, obstacles, restraints, restrictions, straitjacket, trammels and checks. Find more

How are constraints used in the GCC compiler?

Constraints can say whether an operand may be in a register, and which kinds of register; whether the operand can be a memory reference, and which kinds of address; whether the operand may be an immediate constant, and which possible values it may have.

What is another word for constraint or compulsion?

Here’s a list of similar words from our thesaurus that you can use instead. Restraints, usually of metal and often joined by a chain, placed around a prisoner’s wrists or ankles to restrict their movement “People are not morally responsible for that which they do under constraint or compulsion.”