The PowerPC Processor Element (PPE) supports two instruction sets: the PowerPC instruction set and the Vector/SIMD Multimedia Extension instruction set.
Although most of the coding for the Cell Broadband Engine will be in a high-level language like C or C++, an understanding of the PPE architecture and instruction sets adds considerably to a developer’s ability to produce efficient, optimized code. This is particularly true because C-language intrinsics are provided for the PPE’s Vector/SIMD Multimedia Extension instruction set, and these intrinsics map directly to one or more Vector/SIMD Multimedia Extension assembly-language instructions.
The PowerPC instruction set uses instructions that are 4 bytes long and word-aligned. It supports byte, halfword, word, and doubleword operand accesses between storage and its 32 general-purpose registers (GPRs). The instruction set also supports word and doubleword operand accesses between storage and a set of 32 floating-point registers (FPRs). Signed integers are represented in twos-complement form.
The Vector/SIMD Multimedia Extension instruction set uses instructions that, like PowerPC instructions, are 4 bytes long and word-aligned. However, all of its operands are 128 bits wide. Most of the Vector/SIMD Multimedia Extension operands are vectors, including single-precision floating-point, integer, scalar, and fixed-point of vector-element sizes of 8,16, and 32 bits.