Chapter II Summary

Registers and memory
1. Register function
. General purpose and dedicated use of registers
. CS:IP Control Program Execution process
. SS:SP provides stack stack top cell address
. DS:BX (SI,DI) provides the cell address in the data segment
. SS:BP provides the address of the unit in the stack
. ES:BX (SI,DI) provides additional segment unit address
. AX,CX,BX and CX registers are used for operations and staging intermediate computations, but are also dedicated to certain directives (lookup instruction tables).
. The PSW program Status Word register can only be accessed through dedicated instructions (LAHF, SAHF) and Stacks (Pushf,popf).

2. Memory Segmentation Management
. Resolves an issue where 16-bit registers make up 20-bit addresses
. Easy Program Relocation
. 20-bit Physical address = Segment Address * 16 + offset Address
. Program Staging organization: typically consists of code snippets, stack segments, data segments, and additional segments, and the stack inside the system is used when the stack segment is not set.

3. Stacks
. Stack is an advanced data structure, data access at the top of the stack, the data into the stack to reduce the stack to address the direction of expansion.
. The stack is often used to hold breakpoints and staging data or intermediate calculations for subroutine calls and interrupt responses.
. Stacks are always accessed in words

Chapter II Summary