13 votes
Accepted

Why did decimal arithmetic slow down VisiCalc?

A number like 1234.56 takes three bytes in BCD where it would've taken eight bytes in double precision binary floating point. Generally speaking, that is not the case. If you have a database field ...
9 votes

Why did decimal arithmetic slow down VisiCalc?

6502 supported SIMPLE BCD arithmetic. I would bet that the VisiCalc guys in the end didn't even use that feature and wrote the whole thing from scratch. There's not just addition and subtraction, ...
  • 11.5k
7 votes

Why did decimal arithmetic slow down VisiCalc?

Because decimal operations are slower, even on the 6502. There is processor support for 8-bit BCD addition and subtraction, but that's it. Code for decimal multiplication, division, shifting, ...
  • 12.8k
6 votes
Accepted

How did VisiCalc decide how many decimal places to display?

VisiCalc doesn’t “decide”, it does what the user asks it to. As far as displaying values, it supports a few different display formats: general (the default), which displays however many significant ...
1 vote

Why did decimal arithmetic slow down VisiCalc?

Using binary floating-point math would have made some kinds of computations much faster, but would have made many other tasks slower, and using BCD math was a reasonble engineering decision. Nowadays ...
  • 32.1k

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