问题
I'm not sure what is the range bound for the immediate in lui instruction.
When I assemble:
lui $t0,32768
It successfully went without errors.
However,
lui $t0,-32768
notified that -32768 out of range.
回答1:
In MIPS the immediate in I-type instructions is always 16-bit long. That means the range will be [0, 65535] if the assembler treats it as unsigned, and [-32768, 32767] for the signed case
However what you can use in the assembly depends on the assembler
For example some assemblers like shell-storm and WeMips accept constants in [-32768, 65535] which is a mix of both 16-bit signed and unsigned, MIPS Converter only accepts hexadecimal values but WebMIPSASM accepts even huge values like 9223372036854775807 and truncate the result to 16 bits
来源：https://stackoverflow.com/questions/53467887/range-of-immediates-in-lui-instruction