What Is Registers Ax Bx Cx Dx

The "Go" tools
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understand....

registers

by Jeremy Gordon -

This file is intended for those interested in 32 bit assembler programming, in particular for Windows.

The "registers" are small areas of memory contained within the processor itself. The processor is designed to dispense the data in the registers and transfer data into and out of them at great speed. Every bit processors have get more powerful so accept the number and size of the registers they incorporate, but all processors from the 386 upward have eight "general" 32 chip registers for general programming utilise. These have been given names by Intel based on their traditional uses, shortened for all purposes to EAX, EBX, ECX, EDX, EDI, ESI, EBP, and ESP.

There is as well an EIP register which holds the current instruction being executed at whatever one time. You cannot read from or write to the EIP register so information technology is not available for general programming utilise. All the same its value will be visible to yous when you are single-step debugging.

EBP (base arrow) and ESP (stack arrow) accept certain restrictions in utilize which I shall come to after.

Each of the registers can exist accessed using 32 bits. That is to say if you use a 32 bit assembler didactics, then all 32 bits of the register will exist inverse, read or written to (depending on the education). Each of the registers can also exist accessed using simply the outset 16 bits if this is allowed by the pedagogy concerned. This is achieved by using the register names AX, BX, CX, DX, DI, SI, BP and SP.
In addition to this the registers AX, BX, CX and DX take their first 16 bits divided to make ii separate viii chip registers, available for access using AL, AH, BL, BH, CL, CH and DL, DH. The "50" stands for low and the "H" stands for high.

The following illustrations show this:-