https://flippyside.github.io/akosus.github.ioBlog descriptionBlog Titlehttp://www.rssboard.org/rss-specificationpython-feedgenhttps://github.githubassets.com/favicons/favicon.svghttps://flippyside.github.io/akosus.github.ioTue, 01 Oct 2024 07:18:51 +0000Blog Title60Blog Titlehttps://flippyside.github.io/akosus.github.io/post/machine-level-programming%5BCSAPP%5D.html# basic ## history of intel processors and architectures Intel X86 Processors： - dominate laptop/desktop/server market - CISC(complex instruction set computer) - evolution - 8086: 16-bit - 386(i386)(80386)(IA32) 32-bit - pentium4E(x86-64): 64-bit - core 2: multi-core - core i7: four cores Architecture(ISA: instruction set architecture): the parts of a processor design that needs to understand or write assembly/machine code machine code: byte-level programs, can be executed by processor assembly code: a text representation of machine code programmer-visible state: - PC: program counter - address of next instruction - RIP in x86-64 - Register File: heavily used program data - Condition Codes: - store status information about most - used for conditional branching - Memory - byte addressable array - code and user data - stack to support procedures ```c long plus(long x, long y); void sumstore(long x, long y, long *dest){ long t = plus(x, y); *dest = t; } ``` ```asm sumstore: pushq %rbx movq %rdx, %rbx call plus movq %rax, (%rbx) popq %rbx ret ``` ## assembly characteristics Data type: - integer data of 1,2,4, 8 byte - floating point data of 4, 8, 10 byte - code: byte sequences encoding series of instructions - no aggregate types such as arrays or structures Operation: - perform arithmetic function on register or memory data - transfer data between memory and register - transfer control ``` # C code *dest = t; # Assembly movq %rax, (%rbx) # move 8-byte value to memory # operands: # t: register %rax # dest: register %rbx # *dest: memory M[%rbx] # object code 0x40059e: 48 89 03 # 3-byte instuction # stored at address 0x40059e ```  ``` %r: 64bit %e: 32bit ``` x8664将寄存器增加到%r，相比i386增加了一倍  寄存器的名字在很早之前反映了他们的特定功能，现在没有这种对应了。https://flippyside.github.io/akosus.github.io/post/machine-level-programming%5BCSAPP%5D.htmlTue, 01 Oct 2024 07:18:23 +0000