alt Hacker News> diagram for the Arm T32 BL encoding
is that... bit xor?
did they attempt signed immediate, but gave up 3 bits into a 32 bit immediate?
wtf
> diagram for the Arm T32 BL encoding
is that... bit xor?
did they attempt signed immediate, but gave up 3 bits into a 32 bit immediate?
wtf
It originally had a range of 4 MiB, and they extended it to 16 MiB in a later ISA revision. The bits with the XORs were originally constant-1 and they wanted to keep backward compatibility, so bits J1 and J2 are interpreted as "if this bit is clear, toggle this position in the leading sign bits".