Compilation of computer systems-IA32 processor data format and Data Operations

Compilation of computer systems-IA32 processor data format and Data Operations
Compilation of computer systems-IA32 processor data format and Data Operations

IA32 data format:
Intel uses the term "word" to indicate the 16-bit data type. Therefore, 32-bit data is called "double-digit" and 64-bit data is called "four-character ".



Char * indicates all pointer types. Note: The New long in C language is octal, but the hardware IA32 does not support this type.

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Most commands have one or more operands, indicating the source data value to be referenced during the execution of an operation, and the target location where the result is placed. The source data value can be given as a constant or read from a register or memory, and the result can be saved in a register or memory.

There are three operands:
>>> 1. Immediate number is a constant, starting with $, followed by an integer;
>>> 2. number of registers. For word operations, it indicates the value saved in a register. For byte operations, it is one of eight single-byte registers, for example, % al (eight lower bits in the eax register)
>>> 3. memory Reference, which is used to access a location of the memory based on the calculated valid address. It consists of four parts: immediate number offset (lmm), base address register Eb, address register Ei, and proportional factor s. The valid address is calculated as Imm + R [Eb] + R [Ei] * s. (R [Eb] indicates the Eb value of the Register. R [Ei] indicates the Ei value of the Register. The value of s can only be 1, 2, 4, or 8) in the following table, Mb [addr] indicates a reference to the B-byte values starting from the address addr in the memory.

Operand format table



For example, if the address 0x100 value is 56, the operand 0x100 value is 56, which is an absolute addressing; $0x100 value 0x100 is an immediate addressing;