Unofficial LoongArch Intrinsics Guide

This is the Unofficial LoongArch Intrinsics Guide by Jiajie Chen et, al. The documentation is arranged from the following sources:

• QEMU
• GCC
• Observations from real hardware incl. 3C5000 and 3A6000

The guide provides pseudo code for the SIMD intrinsics. The code assumes that the elements of the LSX/LASX vector registers can be accessed via members of a union:

union lsx_register {
  uint8_t byte[16];
  uint16_t half[8];
  uint32_t word[4];
  uint64_t dword[2];
  uint128_t qword[1];
  float fp32[4];
  double fp64[2];
};

union lasx_register {
  uint8_t byte[32];
  uint16_t half[16];
  uint32_t word[8];
  uint64_t dword[4];
  uint128_t qword[2];
  float fp32[8];
  double fp64[4];
};