New answers tagged computer-architecture
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
Some old ISAs, most notably x86 and MOS 6502, did support a few BCD instructions. According to Randall Hyde's website (cited in the Wikipedia article), business and financial applications used BCD ...
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Desktop computing: who needs multi-threading, multi-processing; and how much?
CPUs with lots of cores are commonly used on servers that handle lots of separate requests, such as web servers. If I am loading one page and you are loading a different page (or even the same page), ...
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Basic questions regarding a computer
There was never a time when you could connect a screen terminal directly to a CPU. Direct human interaction with a computer is by reading and writing bytes by flipping switches (up=0 down=1 or vice ...
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Why does ISA includes instruction for logical operation?
Whenever something is done very frequently and can be done much more quickly by making it part of the instruction set, it should be. The first generations of microprocessors had very limited amounts ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
We use binary floats because they do the things we want better. Quoting from the wikipedia article you've been linked. I've highlighted key ones:
Advantages
Scaling by a power of 10 is simple.
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
I think you may be muddling two different things:
Binary arithmetic vs binary coded decimal
Fixed point vs floating point
There are 4,503,599,627,370,496 possible combinations of 52 bits (2 to the ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
The only advantage of BCD, fixed or floating, is that it rounds off the way humans expect it to.
The disadvantages have already been enumerated: inefficiency, expense, and lower accuracy for the same ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
Why would anyone want to use decimal?
The other answers have explained the many advantages of binary over decimal floating point. But what are the possible advantages of decimal over binary?
There is ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
Obviously, BCD and DPD are used by real programs. Some older architectures (mostly in the 8-bit era) did have instructions to support BCD. Today, there are programs that use decimal, but most find it ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
Quite simply, your assertion that BCD gives more precision is wrong.
For example, 20 bits = 5 BCD numbers = 5 digits, while 20 binary digits = 0 to 1,048,575 = more than 6 digits. BCD is very ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
the binary representation is the most efficient. BCD wastes 17% of the bits.
binary arithmetic is the simplest to implement in hardware.
"the smallest difference between numbers is $0.015625$, ...
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Why do computers use binary numbers in IEEE754 fraction instead of BCD or DPD?
See https://en.wikipedia.org/wiki/Binary-coded_decimal, "Its principal drawbacks are..." and the section labelled "Disadvantages", for a discussion of several disadvantages of BCD.
D.W.♦
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How does signed floating point adder implement?
You may deduce the full logic from a good sample software implementation, like this one (tied to RISC-V developers so they check reference results using this one). Then, migrate it to hardware ...
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