mov_r64_i32
u8 mov_r64_i32(u8 *buf, u8 reg, s32 imm);
len = mov_r64_i32(buf, JIT_REG_TMP, imm);
len = mov_r64_i32(buf, JIT_REG_TMP, imm);
len = mov_r64_i32(buf, JIT_REG_TMP, imm);
len = mov_r64_i32(buf, JIT_REG_TMP, imm);
len = mov_r64_i32(buf, JIT_REG_TMP, imm);
*len += mov_r64_i32(BUF(buf, *len), JIT_REG_TMP,
len = mov_r64_i32(buf, dst, imm);