The CPU - Jumps

The Computer CPU – Jumps

Finally just to show you that everything you could possibly want can be easily included in this simple processor architecture consider how you might implement a “jump to xxxx” instruction. Normally the next instruction to be executed is in the next sequential memory location but a jump makes the instruction at xxxx the next one. How can this be achieved? Easy! Just make the PC register correspond to register address 00 (rather than general purpose register D as suggested earlier). Now consider what  “load PC from address aaaa” does. It loads the PC register with the value stored in “aaaa” and so makes this the next instruction. Not quite what was…

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The CPU - Op-code

The Computer CPU – Op-code

The op-code isn’t just any old number; it has a structure. In our example the first two bits of the op-code act as a mini address that selects which register the operation is going to use – 11  A register, 10  B register, 01  C register and 00  D register. The top two bits give the operation to be performed on the register that is selected – e.g. 10 = load the register, 11 = add to the value already in the register     and so on. You can see that there is nothing magic in the instruction decoder. The lower two bits are fed into a set of And/Or gates…

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Surfline Data Plans 2019

Surfline Data Plans 2019

Surfline Communications, the first 4G LTE internet service provider in The Republic of Ghana has taken a look at their data packages, releasing a refreshed access packages for internet consumers. Surfline Communication as at the time of this post have coverage in Accra, Kumasi, Sunyani, Cape Coast, Koforidua and Sekondi-Takoradi with the service provider expanding their footprint in new locations. How to purchase and manage your data New and Existing subscribers may manage their accounts online through their MYSELFCARE portal. The portal by far is self explainable and easy to use compared with other self service portals in the country. A USSD is also available from a GSM line. Dial *718*77#…

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The CPU - Principles Of Execution

The Computer CPU – The Fetch cycle

As well as the PC register, a processor also has an instruction register which is used to store the current program instruction. A system clock generator provides pulses that synchronize what happens in the entire machine – it doesn’t have to be this way but non-clock synchronized machines are much more difficult to build and, by for the same reason, to describe! What happens is that the PC register contains the address of the next instruction and on the first clock pulse this address is placed on the address bus and a read cycle transfers the instruction into the instruction register. Notice that we are already using “little human” descriptions of…

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Switch Expressions comes with Java 12

Switch Expressions comes with Java 12

Java 12, the latest six-monthly release of Java, has been released with support for Switch Expressions and the inclusion of the Shenandoah low-pause garbage collector.  There are eight main improvements to the new release, starting with switch expressions. This is still a preview feature, and it extends the switch statement so that it can be used as either a statement or an expression. Whichever form is used, you can use either a traditional or a simplified scoping and control flow behavior. Oracle says that in addition to simplifying everyday coding, the addition prepares the way for the use of pattern matching in the switch statement. Pattern matching is available as another…

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IFTTT applets retired on Gmail from March 31

IFTTT applets retired on Gmail from March 31

Most of the integration of Gmail features in IFTTT are being removed on March 31. IFTTT apps will still be able to send an email, but will no longer be able to trigger actions based on emails received. Google is removing the means to carry out such actions as a side effect of its larger plans to tighten security. The overall plans were announced back in October when Google said it was reviewing all third party applications to see that they conform to stricter security settings. The changes were driven by concern that third-party apps could use Gmail’s APIs to gain access to the content and details of Gmail users’ emails.…

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