[cairo] [PATCH] Rely less on fast double-precision FPUs

Bill Spitzak spitzak at gmail.com
Tue Jun 1 13:23:43 PDT 2010

I'm sure this has already been discussed for cairo, but is there a 
reason double is used instead of 32-bit float? Many other graphic apis I 
have seen use float coordinates and matrices for precisely this reason.

Jonathan Morton wrote:
> ARM CPUs have a big weakness in double-precision floating point.  In
> particular, DP FP compares are ridiculously slow, mostly because the
> result of the compare has to be transferred from the FPU to the CPU
> using a serialising instruction.

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