XMTRX

Files
file	shz_xmtrx.h
file	shz_xmtrx.hpp

Detailed Description

API for managing the SH4's "active matrix.".

XMTRX is the name given to identify the 16 FP registers contained within the back-bank of the SH4's FPU. These 16 registers combine to represent the SH4's 4x4 "active matrix," which can be subsequently transformed against using the FTRV instruction (shz_xmtrx_trans_vec4()).

For maximum FP performance on the SH4, strategic usage of XMTRX to batch transform operations together without having reload FP registers, is key.

Typically, for one-off operations, the in-memory API for Matrices is what should be used; however, when operations can be batched, using XMTRX to hold your matrix within registers is going to give the best performance.

Examples of such scenarios are:

• Applying multiple operations to a source matrix before storing the result.
• Transforming batches of vectors against a single matrix.

See also

Matrices