Module primitives 

Pure, state-free ARM primitives: the barrel shifter, condition codes, and the ALU core.

The barrel shifter, the condition-code checker, and the Add/Sub/logical-op ALU core — each verified against the ARM Architecture Reference Manual’s own documented truth tables. See the parent module (coproc::armv3) doc for the full picture.

Structs

Flags

The four ARM condition-code flags (CPSR bits 31-28 / N,Z,C,V).

Functions

add

ARM ADD-family: op1 + op2 + carry_in.

check_condition

Evaluate a 4-bit ARM condition code against the current flags (Mesen2 CheckConditions).

logical_flags

ARM logical-op flag update (AND/EOR/ORR/MOV/BIC/MVN/TST/TEQ, Mesen2 LogicalOp).

rotate_right

ROR by a fixed 1-31 amount with no carry-out tracking (Mesen2’s 2-argument RotateRight).

rotate_right_carry

ROR by a 0..=31 amount, also returning the carry-out (bit shift-1 of value) — Mesen2’s 3-argument RotateRight, used by ArmDataProcessing’s immediate-operand rotate.

shift_asr

ASR (arithmetic shift right, sign-extending) by a register-derived amount 0..=255.

shift_lsl

LSL (logical shift left) by a register-derived amount 0..=255 (Mesen2 ShiftLsl).

shift_lsr

LSR (logical shift right) by a register-derived amount 0..=255 (Mesen2 ShiftLsr). See shift_lsl for the shared shift == 0 no-op contract.

shift_ror

ROR (rotate right) by a register-derived amount 0..=255 (Mesen2 ShiftRor).

shift_rrx

RRX (rotate right extended by 1, through the carry flag; Mesen2 ShiftRrx).

sub

ARM SUB-family: Add(op1, !op2, carry_in, ...).