eax, ebx, ecx and so on are actually registers, which can be seen as "hardware" variables, somewhat similar to higher level-language's variables. Registers can be used in your software directly with instructions such as mov, add or cmp.

2016年4月24日 · # x at %ebp+8, n at %ebp+12 movl 8(%ebp), %esi movl 12(%ebp), %ebx movl $-1, %edi movl $1, %edx .L2: movl %edx, %eax andl %esi, %eax xorl %eax, %edi movl %ebx, %ecx ...

2016年11月25日 · ECX: "Extended Counter" - often used for loop and string operations, as well as for storing function arguments. EDX: "Extended Data" - often used for I/O operations and for storing function arguments. ESI: "Extended Source Index" - often used as a pointer to a source operand in string operations.

2016年5月22日 · mov ecx, squares/horizCharsPerSquare would work if those were both assemble-time constants. A right-shift is the correct choice if horizCharsPerSquare is a power of 2. mov ecx squares would assemble, but that's not how div works. See also the x86 tag wiki. –

2017年3月19日 · The disadvantage of loop is that it's slower than the equivalent sub ecx,1; jnz start_of_loop. The advantage of loop is that it uses less instruction bytes. Think of it as a code-size optimization you can use if ECX happens to be a convenient register for looping, but at the cost of speed on some CPUs.

2014年6月10日 · ecx was the count register which held a loop counter; edx was the data register which you could use for I/O port access; edi was the destination index register which pointed to the "destination" of a string operation; esi was the source index register which pointed to the "source" of a string operation

2020年9月29日 · I have googled enough but could not figure out what the bracket means. Also, I see some syntax as movl 8(%ebp), %eax Could some someone suggest me some good reference?

2018年3月16日 · createArray PROC ;saving 5 multiples of the value currently in eax into an array addres that is ;on the stack push ecx push eax push esi push ebp mov ebp, esp mov ecx, 5 mov esi, [ebp+24] ;address of array L1: call multiply ;call multiply with two numbers eax, ecx pop eax mov [esi],eax add esi, 4 Loop L1 ....cont createArray endp multiply PROC ...

2012年10月25日 · Possible Duplicate: x86 Assembly - ‘testl’ eax against eax? I'm very very new to assembly language programming, and I'm currently trying to read the assembly language generated from a binary. ...

2014年3月12日 · Visual C++ often uses push ecx and pop ecx as alternatives to sub esp, 4 and add esp, 4. Why? There are several reasons: push ecx and pop ecx are single-byte instructions, while add and sub are three byte each. The difference may not be huge, but all the saved bytes in all functions may add up to something substantial.