Book Image

Modern Computer Architecture and Organization

By : Jim Ledin
Book Image

Modern Computer Architecture and Organization

By: Jim Ledin

Overview of this book

Are you a software developer, systems designer, or computer architecture student looking for a methodical introduction to digital device architectures but overwhelmed by their complexity? This book will help you to learn how modern computer systems work, from the lowest level of transistor switching to the macro view of collaborating multiprocessor servers. You'll gain unique insights into the internal behavior of processors that execute the code developed in high-level languages and enable you to design more efficient and scalable software systems. The book will teach you the fundamentals of computer systems including transistors, logic gates, sequential logic, and instruction operations. You will learn details of modern processor architectures and instruction sets including x86, x64, ARM, and RISC-V. You will see how to implement a RISC-V processor in a low-cost FPGA board and how to write a quantum computing program and run it on an actual quantum computer. By the end of this book, you will have a thorough understanding of modern processor and computer architectures and the future directions these architectures are likely to take.
Table of Contents (20 chapters)
1
Section 1: Fundamentals of Computer Architecture
8
Section 2: Processor Architectures and Instruction Sets
14
Section 3: Applications of Computer Architecture

Answer

The Ex__5_checksum_subroutine.asm file implements the checksum algorithm as a subroutine:

; Ex__5_checksum_subroutine.asm
; Try running this code at https://skilldrick.github.io/easy6502/
; Set up the array of bytes to be checksummed
LDA #$01
STA $00
LDA #$72
STA $01
LDA #$93
STA $02
LDA #$F4
STA $03
LDA #$06 ; This is the checksum byte
STA $04
; Store the address of the data array in $10-$11
LDA #$00
STA $10
STA $11
; Store the number of bytes in X
LDX #5
; Call the checksum calculation subroutine
JSR CALC_CKSUM
; Halt execution
BRK
; ==============================================
; Compute the checksum
CALC_CKSUM:
; Move X to Y
TXA
TAY
LDA #$00
DEY
LOOP:
CLC
ADC ($10), Y
DEY
BPL LOOP
CMP #$00
BNE CKSUM_ERROR
; The sum is zero: Checksum is correct
LDA #1
JMP DONE
; The sum is nonzero: Checksum is incorrect
CKSUM_ERROR:
LDA #0
; A contains 1 if checksum is correct, 0 if it is incorrect
DONE:
RTS