Files
Odin/core/rexcode/isa
Brendan Punsky 440bd9df3f rexcode/arm32: printing a register-shifted operand read past SHIFT_NAMES
SHIFT_NAMES holds five entries, LSL..RRX, but Shift_Type has ten: the four
register-shifted-register markers (LSL_REG = 6 .. ROR_REG = 9) say the shift
count comes from an Rs register rather than an immediate. Both places that
indexed the table used the raw enum value, and the guard in front of them only
excluded NONE and RRX -- so any operand carrying a register shift indexed a
5-entry array with 6..9 and killed the printer:

  printer.odin(473:45) Index 6 is out of range 0..<5

Fold the register-shifted variants back onto the table and give each spelling
its own case: `, lsl #3` for an immediate amount, `, lsl r3` when the count is
in a register (Rs index rides in shift_amt), and a bare `, rrx`, which takes no
amount. All nine now print what an assembler accepts -- verified against
llvm-mc -- where three of them previously crashed and RRX printed nothing.

The memory-operand site indexed the same table the same way and is routed
through the same helper.

Found by printing every entry in the decode table; that sweep now completes.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
2026-08-27 08:21:14 -04:00
..
2026-08-18 18:23:42 +01:00