Computer arithmetic

Carry flag

In computer processors the carry flag (usually indicated as the C flag) is a single bit in a system status register/flag register used to indicate when an arithmetic carry or borrow has been generated out of the most significant arithmetic logic unit (ALU) bit position. The carry flag enables numbers larger than a single ALU width to be added/subtracted by carrying (adding) a binary digit from a partial addition/subtraction to the least significant bit position of a more significant word. This is typically programmed by the user of the processor on the assembly or machine code level, but can also happen internally in certain processors, via digital logic or microcode, where some processors have wider registers and arithmetic instructions than (combinatorial, or "physical") ALU. It is also used to extend bit shifts and rotates in a similar manner on many processors (sometimes done via a dedicated flag). For subtractive operations, two (opposite) conventions are employed as most machines set the carry flag on borrow while some machines (such as the 6502 and the PIC) instead reset the carry flag on borrow (and vice versa). (Wikipedia).

Video thumbnail

hello, Scratch

From playlist Week 0 2013

Video thumbnail

The Christmas Truce | History

During WWI soldiers from opposing sides laid down their guns and celebrated Christmas together. Subscribe for more History: http://histv.co/SubscribeHistoryYT Check out exclusive HISTORY videos and full episodes: http://www.history.com/videos Get daily updates on history: http://www.his

From playlist Holidays: Christmas | History

Video thumbnail

Deconstructing History: American Flag | History

Why does the American flag have 13 stripes? Get all the facts and figures on "Old Glory." HISTORY®, now reaching more than 98 million homes, is the leading destination for award-winning original series and specials that connect viewers with history in an informative, immersive, and entert

From playlist HISTORY Celebrates the 4th of July

Video thumbnail

Bet You Didn't Know: Veterans Day | History

Do you know why Veterans Day is celebrated on November 11th every year? Get the whole story behind the holiday. #HistoryChannel Subscribe for more History: http://histv.co/SubscribeHistoryYT Check out exclusive HISTORY videos and full episodes: http://www.history.com/videos Get daily upd

From playlist History Celebrates Veteran's Day

Video thumbnail

The History of the Pledge of Allegiance | History

Take a look back at the origins of and history behind the customary salute to the American flag. Newsletter: https://www.history.com/newsletter Website - http://www.history.com Facebook - https://www.facebook.com/History Twitter - https://twitter.com/history HISTORY Topical Video Season

From playlist Examine the Past | History

Video thumbnail

Brad Meltzer's Lost History: What Happened to the Ground Zero Flag? | History

What happened to the flag hoisted at Ground Zero on September 11, 2001? Newsletter: https://www.history.com/newsletter Website - http://www.history.com Twitter - https://twitter.com/history/posts Facebook - https://www.facebook.com/History HISTORY Topical Video Season 1 Episode 1 Whethe

From playlist Remembering 9/11: Fifteen Years Later | History

Video thumbnail

Ex: Determine the Possible Number of 4 Color Striped Flags (Permutation)

This video explains how to find the number flags with 4 stripes of different colors. A permutation and the counting principle is used. Site: http://mathispower4u.com

From playlist Permutations and Combinations

Video thumbnail

Conditional jump instructions

In this video we program the microcode of the 8-bit breadboard computer so that it supports two conditional jump instructions: JC (jump carry) and JZ (jump zero). We also test out these new instructions and write several programs using them. Code from this video: https://github.com/beneat

From playlist Building an 8-bit breadboard computer!

Video thumbnail

CPU flags register

Share your requests for future video topics here: https://www.reddit.com/r/beneater/comments/88m9jy/ben_eater_video_suggestions/ Intel x86 developers guide (4800 pages!): https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf#page=80 More 8-bit compu

From playlist Building an 8-bit breadboard computer!

Video thumbnail

ELEC2141 Digital Circuit Design - Lecture 25

ELEC2141 Week 9 Lecture 3: Arithmetic Circuits

From playlist ELEC2141 Digital Circuit Design

Video thumbnail

How assembly language loops work

More 6502: https://eater.net/6502 Support these videos on Patreon: https://www.patreon.com/beneater or https://eater.net/support for other ways to support. ------------------ Social media: Website: https://www.eater.net Twitter: https://twitter.com/ben_eater Patreon: https://patr

From playlist Build a 65c02-based computer from scratch

Video thumbnail

Top Shot - Recurve Bow | History

This ancient hunting weapon carries the same about of power as the long bow only in a smaller package. It's the only bow allowed in the Olympics and is still used by modern day hunters. HISTORY®, now reaching more than 98 million homes, is the leading destination for award-winning origina

From playlist Top Shot | History

Video thumbnail

NES Emulator Part #2: The CPU (6502 Implementation)

In this video I build a 6502 emulation in C++. I pay close attention to the instructions that can cause problems, ADC and SBC. Then I build a lightweight application to analyze running 6502 programs. Source: https://github.com/OneLoneCoder/olcNES YouTube: https://www.youtube.com/javidx9

From playlist NES Emulator From Scratch

Video thumbnail

GoGaRuCo 2014- Let's Build a Computer!

By, Ryan Davis The increasing accessibility of computing and scripting languages means more and more of us don't have computer science fundamentals and hand-wave our laptops and servers as magic. But, it doesn't take much to learn that the wizard box you type on every day is just layers of

From playlist GoGaRuCo2014-

Video thumbnail

Stalin's Nazi Flags

The strange story of the NKVD 'Flag Disposal Regiment' and the Nazi flags thrown at the foot of Lenin's Mausoleum during the Moscow Victory Parade 1945. Visit my new audio book channel 'War Stories with Mark Felton': https://youtu.be/xszsAzbHcPE Help support my channel: https://www.paypa

From playlist History of Nazi Symbols

Video thumbnail

How Computers Calculate - the ALU: Crash Course Computer Science #5

Today we're going to talk about a fundamental part of all modern computers. The thing that basically everything else uses - the Arithmetic and Logic Unit (or the ALU). The ALU may not have to most exciting name, but it is the mathematical brain of a computer and is responsible for all the

From playlist Computer Science

Video thumbnail

Memorial Day: It's Never Too Late to Thank a Vet | History

American citizens send a special message to their loved ones for their military service. Subscribe for more History: http://histv.co/SubscribeHistoryYT Check out exclusive HISTORY videos and full episodes: http://www.history.com/videos Get daily updates on history: http://www.history.co

From playlist History Celebrates Memorial Day

Video thumbnail

Game Physics (in Assembler) - Computerphile

Just how do you turn basic number crunching into a physics system for gaming? Video Games programmer Matt Phillips explains. More info on Matt's Project: http://www.tanglewoodgame.com/info Matt's Kickstarter for Tanglewood: http://bit.ly/Computerphile_Tanglewood Thanks to The National V

From playlist Sega Megadrive Video Game Programming

Video thumbnail

Deconstructing History: Huey Helicopters in Vietnam | History

The UH-1 "Huey" helicopter became a symbol of U.S. combat forces in Vietnam. Subscribe for more History: http://histv.co/SubscribeHistoryYT Check out exclusive HISTORY videos and full episodes: http://www.history.com/videos Get daily updates on history: http://www.history.com/news/ Che

From playlist Presidents at War | History

Video thumbnail

Hitler's Blood Flag - The Mystery of the Blutfahne

What happened to the infamous 'Blood Flag', a Nazi relic kept in the Braun House in Munich. Was it destroyed by Allied bombing, looted by locals, taken as a souvenir by US troops? Discover the full story here. Help support my channel - see below for details: https://www.paypal.me/markfelt

From playlist Hitler Various Subjects

Related pages

Overflow flag | Arithmetic logic unit | Half-carry flag | Carry (arithmetic) | Least significant bit | Most significant bit | Arithmetic | Bit