9.42.3 Floating Point

SH2E, SH3E and SH4 groups have on-chip floating-point unit (FPU). Other SH groups can use .float directive to generate IEEE floating-point numbers.

SH2E and SH3E support single-precision floating point calculations as well as entirely PCAPI compatible emulation of double-precision floating point calculations. SH2E and SH3E instructions are a subset of the floating point calculations conforming to the IEEE754 standard.

In addition to single-precision and double-precision floating-point operation capability, the on-chip FPU of SH4 has a 128-bit graphic engine that enables 32-bit floating-point data to be processed 128 bits at a time. It also supports 4 * 4 array operations and inner product operations. Also, a superscalar architecture is employed that enables simultaneous execution of two instructions (including FPU instructions), providing performance of up to twice that of conventional architectures at the same frequency.