[Feature] Matmul for CPU

[zcbenz]

Some of the most popular models provide weights in bfloat16, which unfortunately can not load on CPU because Matmul::eval_cpu only supports float32.

I know CPU support is not on priority, but it would be great if my code can run on other platforms than mac arm64 even being very slow.

[thegodone]

maybe this can be also interesting to look at https://github.com/microsoft/BitNet

[polvalente]

Are there plans for supporting integer tensors in tensordot/matmul?

[awni]

We're not opposed to having integer support for matmul, but it's not an active priority at the moment.