4.5. TIE Instructions
The byte-swapping function described in the previous chapter provides an excellent demonstration of the ability of new processor instructions to reduce cycle count. Figure 4.3 illustrates the byte-swap function, which converts a 32-bit word between big- and little-endian formats.
Figure 4.3. Conversion from one endian format to the other for a 32-bit word.
The nine instructions from the base Xtensa ISA that are required to perform this operation are:
| slli a9, a14, 24 | Form intermediate result bits 24–31 in register a9 |
| slli a8, a14, 8 | Shift 32-bit word left by 8 bits, save in register a8 |
| srli a10, a14, 8 | Shift 32-bit word right ... |
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