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Sep 28, 2018 · I am trying to understand how the assembly language works for a micro-computer architecture class, and I keep facing different syntaxes in examples: sub $48, %esp mov %eax, 32(%esp) What do these...
Nov 15, 2016 · To use if statement in NASM assembly first line should write: comp eax, ebx In this line NASM understands that it should compare two registers. Now u should specify how NASM assembly should compare them. Lets compare for example if greater or equal: main: comp eax, ebx jge greater_or_equal greater_or_equal: ; your code if greater or equal
Jul 8, 2015 · If I remember correctly xor ax, ax is a one byte assembly instruction, whilst mov ax, 0 would be at least 3 and would probably take slightly longer to execute. It will certainly take longer to decode than the xor instruction.
The importance of CMP applies mostly in conditional code execution (Jump - See : assembly_conditions). When the processor executes a conditional-jump jcc instruction, it checks the status flags register and jumps to the target label if it meets the conditions, otherwise falls through to the next instruction.
Oct 4, 2015 · I am trying to understand assembly to be able to solve a puzzle. However I encountered the following instructions: 0x0000000000401136 <+44>: cmpl $0x7,0x14(%rsp) 0x000000000040113b <+49>: ja 0x401230 <phase_3+294> What I think it's doing is: The value of 0x14(%rsp) is -7380. According to my understanding cmpl compares unsigned.
The macro variant is the same for both, but you won't learn assembly this way. You'll learn C-style asm instead. invoke is for stdcall or fastcall while cinvoke is for cdecl or variable argument fastcall. The assembler knows which to use. You can disassemble the output to see how invoke expanded.
Dec 4, 2018 · The instruction and performs bit-wise AND operation on its operands. For example the instruction and al, bl should compute the AND operation on the register al and bl (as illustrated by @Serkratos121) and store the result in al register.
Sep 1, 2009 · That compiled code will also be stored in the assembly and reused on subsequent calls. The assembly can also contain resources like icons, bitmaps, string tables and so on. Furthermore, the assembly also contains metadata in the assembly manifest - information like version number, strong name, culture, referenced assemblies and so forth.
Jan 10, 2013 · From the Intel's manual - Instruction Set Reference, the JE and JZ have the same opcode (74 for rel8 / 0F 84 for rel 16/32) also JNE and JNZ (75 for rel8 / 0F 85 for rel 16/32) share opcodes.
Jul 14, 2009 · In TASM (x86 assembly) it can look like this: cmp BL, BH je EQUAL ; BL = BH jg GREATER ; BL > BH jmp LESS ; BL < BH in this case it compares two 8bit numbers that we temporarily store in the higher and the lower part of the register B. Alternatively you might also consider using jbe (if BL <= BH) or jge/jae (if BL >= BH).
