Jul 7, 2017 · The registers starting with r as in rax, rbx, etc, are the 64-bit registers introduced with the AMD64 extension to the existing 32-bit x86 ISA. That ISA extension was subsequently …

Dec 20, 2016 · mov %rax, %eax # AT&T syntax (INVALID!) mov eax, rax ; Intel syntax (INVALID!) but not identical. This last case is actually an invalid instruction because there is an operand …

RAX is the full 64-bit value, with EAX and its sub-components mapped to the lower 32 bits. The upper half of 64-bit registers is only accessible in 64-bit mode, unlike 32-bit registers which …

With the advent of x64 and 64-bit architecture, register size doubled once again and the EAX register was renamed RAX. However a new naming convention was also adopted, and the …

Mar 20, 2020 · So R in RAX stood for register, and was a way to unify the naming to be more consistent with the new R8–R15 registers. The new registers also got their “narrow” versions. …

Dec 11, 2024 · For example, the 64-bit extension of eax is called rax. The new registers are named r8 through r15. The lower 32 bits, 16 bits, and 8 bits of each register are directly …

Oct 8, 2021 · 累加寄存器 (eax / rax) eax是32位累加寄存器，rax是它的64位扩展版本。 常用于算术运算和函数返回值。 基址寄存器 (ebx / rbx) ebx是32位基址寄存器，rbx是它的64位扩展版 …

Like C++ variables, registers are actually available in several sizes: rax is the 64-bit, "long" size register. It was added in 2003 during the transition to 64-bit processors.; eax is the 32-bit, "int" …

Thus, after movl $-1, %eax, the %rax register has value 0x00000000FFFFFFFF. Loading a value into a 16- or 8-bit register name leaves all other bits unchanged. There are special instructions …

Jan 1, 2024 · For example, 'EAX' is the accumulator register as a 32-bit value. Similarly, in the 64-bit version, the 'E' is replaced with an 'R' (register), so the 64-bit version of 'EAX' is called …