x87 – Tarik Billa

Extended (80-bit) double floating point in x87, not SSE2 – we don’t miss it?

July 19, 2023 by Tarik

The biggest problem with x87 is basically that all register operations are done in 80 bits, whereas most of the time people only use 64 bit floats (i.e. double-precision floats). What happens is, you load a 64 bit float into the x87 stack, and it gets converted to 80 bits. You do some operations on … Read more

Usefulness of signaling NaN?

April 9, 2023 by Tarik

As I understand it, the purpose of signaling NaN is to initialize data structures, but, of course runtime initialization in C runs the risk of having the NaN loaded into a float register as part of initialization, thereby triggering the signal because the the compiler isn’t aware that this float value needs to be copied … Read more