On 5/19/20 7:37 PM, LIU Zhiwei wrote:
> On 2020/5/12 1:40, Richard Henderson wrote:
>> On 4/30/20 12:21 AM, LIU Zhiwei wrote:
>>> + # sequence of li rd, 0x1234567887654321
>>> + #
>>> + # 0: 002471b7 lui rd,0x247
>>> + # 4: 8ad1819b addiw rd,rd,-1875
>>> + # 8: 00c19193 slli rd,rd,0xc
>>> + # c: f1118193 addi rd,rd,-239 # 0x246f11
>>> + # 10: 00d19193 slli rd,rd,0xd
>>> + # 14: d9518193 addi rd,rd,-619
>>> + # 18: 00e19193 slli rd,rd,0xe
>>> + # 1c: 32118193 addi rd,rd,801
>> You don't really need to use addiw. Removing that special case would really
>> simplify this.
> I think I don't get it. Do you mean that the immediate will not be 64 bit?
Well, mostly the immediate will be small, actually. But the interface must
support 64-bit immediates.
I'm saying that for this computation,
lui
addi
slli
addi
...
is the same. You don't *have* to use addiw.
r~
