Special-Purpose Registers (PC, ACC, MAR and MDR)

Covering 4 special purposes registers: the Program Counter, the Accumulator, the Memory Address Register and the Memory Data Register (also called the Memory Buffer Register).

Made primarily for OCR GCSE Computer Science (J277) Paper 1.

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[sullygangster]

Hey i just wanted to say a huge thank you for going out of your way to make these videos for us, it means alot and this has saved my computer science gcse! Thank you so much!!

[chronicsnail]

Each register does a specific job:
PC - Fetches the address location of the next instruction
ACC - Stores the result of executed instruction does this for speed.

MAR (Memory Address Register) - Holds the address to which the CPU is needing to fetch.
MDR - Hold the data being transferred between the MAR and the CPU..

MAR and MDR are linked as they are both reading and writing to each other.
MAR and MDR are 'buffers' essentially packets of held data which decreases the time to execute data as the RAM and CPU transfer is slow, these are 'stops' for data.

[progamerxi]

Omg thank you so much for these videos I got a grade 9 in my exam. U make these videos sound so easy where’s my teachers are stupid but ur amazing dude

[steffinsamson]

Wow, I can't stress how helpful your videos are. I've learnt all of this before in my lessons and during my revision but your videos just help me to actually understand everything, it all just makes much more sense now. Thank you so much!

[alexburns]

Good luck anyone sitting exam tommorow

[fahmida]

This playlist is very helpful for my mock exam thank you

[owenpook]

Anyone else binging these videos before the GCSE tomorrow?

[joebrowse]

something to help-
PC tim knows where you live (next instruction)
ACCalculator (stores result)
MAR to MDR
(address of data, holds the data)

please suggest an edit if something is unclear, hope it helps crammers

[moizasbat-lbxh]

Good luck tomorrow computer scientist 😊

[jaydenpleinyte]

your videos are helping me cram, but i actually understand the material, i cant thank you enough

[hoodsitegaming]

Hi I keep getting dajavoo everyday. Then I pictured the word sithical I got curius I look it up then it brought me here to your channel. I'm sleepy right now but i just want to be taught to code so I can fix older and newer games and and also I believe coding goes real deep if we learn the diffrent information to get it

[Jack-pybb]

Instead of teaching us our teacher just makes us watch your videos and make notes.

[miapearson]

Thank you so much for these videos, sir! I just found out that my revision bible (aka the CGP guide) has some inconsistencies with the specification, and we were unable to answer some questions in our mock as a result. So relieving to find a resource who accurately follows the spec!

[maddy]

Watching this the morning of my exam #prepared

[carlossp]

Great video! what about the CIR, Status Register or the Index Register? I saw these on my teacher's documents

[wonderbuddy]

Simple and straightforward. thank you so much!

[tigpooter]

Hi. I got less than a month before my first computer science exam. I have made flash cards for all component 2 topics, but I just started on component 1. I got an 8 in my mocks and I really want a 9 for the real exams. Do you think your component 1 playlist will help me achieve the grade? I'm quite worried about this as im confident I'll get a high pass, but a 9 is really what I'm aiming for.

[sashisuh]

setiap registers dalam cpu(ALU, CU, Registers)memilili tugas spesifik
pc program counter - mengambil lokasi alamat / addres location dari instruksi selanjutnya
acc/ accumulator menyimpan hasil dati instruksi yang di eksekusi melakukan ini untuk kecepatan

mar memory address register hold the memory address dr data tg dibutuhkan u diakses o cpu

mdr memory data registers hold the data yg di trasnfer oleh atau dari lokasi memori oleh cpu

ketika membaca data yg diadressed o mar dipegang dlm mdr
letika menulis data di mdr dituliskan o adress dlm mar
act as buffer

[noumaaaan]

my professor using something called M[MAR] in his notes and I wonder if that's the same as MDR, here's an example -
Fetch Cycle:
MAR <-- PC
MBR <-- M[MAR], PC <-- PC+1
IR <-- MBR
here is M[MAR] the same as MDR?

[hoodsitegaming]

The growth mindset by Carol dweck book is good im still learning I just use imagination and that