What are clobbered registers?
A clobbered register is a register which is trashed i.e. modified in unpredictable way by inline assembler. This usually happens when you need a temp. register or use particular instruction which happens to modify some register as a by-product.
Does GCC support inline assembly?
There are, in general, two types of inline assembly supported by C/C++ compilers: GCC uses a direct extension of the ISO rules: assembly code template is written in strings, with inputs, outputs, and clobbered registers specified after the strings in colons.
What does the clobber list do?
The clobber list is a comma-separated list of strings. This string tells the compiler that the assembly code might modify any memory, not just variables that are included in the output constraints. “cc” This string tells the compiler that the assembly code might modify any of the condition flags N , Z , C , or V .
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 clobber mean in England?
clobber in British English (ˈklɒbə ) noun. British slang. personal belongings, such as clothes and accessories. Word origin.
What is no clobber?
The noclobber option prevents you from overwriting existing files with the > operator. If the redirection operator is ‘>|’, or the redirection operator is ‘>’ and the noclobber option is not enabled, the redirection is attempted even if the file named by word exists.
What is G in assembly?
“=g” (esp) defines an output for the inline assembly. The g tells the compiler that it can use any general register, or memory, to store the result.
What is the EAX register?
EAX register, a 32-bit processor register of x86 CPUs. Environmental Audio Extensions, a number of digital signal processing presets for audio, found in Sound Blaster sound cards.
What is ARM assembly language?
An assembler translates a file containing assembly language code into the corresponding machine language. But ARM processors support an entirely different machine language. The design of the machine language encoding is called the instruction set architecture (ISA).
What is __ asm volatile?
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 does quickie mean in slang?
A quickie is a brief act of sexual intercourse. People will not usually have much foreplay with a quickie. The phrase is often used between regular partners to say that they wish to have sex, but don’t have much time for it. For gay men, a quickie sometimes means casual sex, like a hand job.
What is Crikey slang for?
Crikey. Meaning. An exclamation of surprise.