FA-89756 / Instruction set emulation / Open access

Every ecall reported as a machine-mode call · case 01

User and supervisor system calls carry the machine-mode cause code.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The ecall cause ignores the privilege level it came from.

VERIFIED REPAIR

Cause is 8 + current privilege (8 U, 9 S, 11 M).

Unsuccessful approach: Collapsing S and M to 9 still mislabels machine calls.

Case contract

Input [pc, priv, mie, mtvec, events]; MPIE, MPP, mcause, mepc start 0. step: pc += 4. ecall: exception cause 8 + priv (U 8, S 9, M 11). illegal: cause 2. irq k: interrupt cause 2^31 | k, taken only if priv < 3 or MIE. Trap: mepc = pc, mcause = cause, MPIE = MIE, MIE = 0, MPP = priv, priv = 3, pc = mtvec base (mtvec & ~3), plus 4*k for interrupts when mtvec mode (low 2 bits) is 1. mret: MIE = MPIE, MPIE = 1, priv = MPP, MPP = 0, pc = mepc. Return [pc, priv, MIE, MPIE, MPP, mcause, mepc] after each event.

Why this case matters

Trap and return sequencing defines how emulated operating systems handle syscalls and interrupts; one misordered status update corrupts the interrupt enable state.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(*args):
    pc, priv, mie, mtvec, events = args
    mpie = mpp = mcause = mepc = 0
    log = []
    for ev in events:
        kind = ev[0]
        trap = None
        if kind == 'step':
            pc += 4
        elif kind == 'ecall':
            trap = 11
        elif kind == 'illegal':
            trap = 2
        elif kind == 'irq':
            if priv < 3 or mie:
                trap = (1 << 31) | ev[1]
        elif kind == 'mret':
            mie = mpie
            mpie = 1
            priv = mpp
            mpp = 0
            pc = mepc
        if trap is not None:
            mepc = pc
            mcause = trap
            mpie = mie
            mie = 0
            mpp = priv
            priv = 3
            base = mtvec & ~3
            pc = base + 4 * (trap & 0x7FFFFFFF) if (mtvec & 3) == 1 and trap >> 31 else base
        log.append([pc, priv, mie, mpie, mpp, mcause, mepc])
    return log
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('user ecall and return', [1028, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4354, [['ecall'], ['mret']]], [[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1032, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1036, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1036], [4100, 3, 0, 1, 0, 8, 1036], [1036, 0, 1, 1, 0, 8, 1036]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4610, [['ecall'], ['mret']]], [[4608, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1036, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1040, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1040], [4100, 3, 0, 1, 0, 8, 1040], [1040, 0, 1, 1, 0, 8, 1040]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4866, [['ecall'], ['mret']]], [[4864, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1040, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1044, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1044], [4100, 3, 0, 1, 0, 8, 1044], [1044, 0, 1, 1, 0, 8, 1044]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5122, [['ecall'], ['mret']]], [[5120, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1044, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1048, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1048], [4100, 3, 0, 1, 0, 8, 1048], [1048, 0, 1, 1, 0, 8, 1048]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5378, [['ecall'], ['mret']]], [[5376, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096], [4116, 0, 1, 1, 0, 2, 4096]])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
user ecall and return	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 11, 1032], [4100, 3, 0, 1, 0, 11, 1032], [1032, 0, 1, 1, 0, 11, 1032]]`	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]`	Failed
supervisor and machine ecall	`[[4096, 3, 0, 0, 1, 11, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]`	`[[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]`	Failed
supervisor interrupt with mie clear	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	Passed
machine interrupt masked then enabled	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	Passed
machine interrupt enabled saves mie	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	Passed
vectored mode exceptions go to base	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 11, 2048]]`	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]`	Failed
reserved mode bits masked	`[[4352, 3, 0, 1, 1, 11, 2560], [2560, 1, 1, 1, 0, 11, 2560]]`	`[[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]`	Failed
nested trap overwrites mpp	`[[4096, 3, 0, 1, 0, 11, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	`[[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	Failed

SHA-256 / 0e1e319745d42544aee08f5da402ec82fde48bd16ca0854651ec7386efa8254f

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(*args):
    pc, priv, mie, mtvec, events = args
    mpie = mpp = mcause = mepc = 0
    log = []
    for ev in events:
        kind = ev[0]
        trap = None
        if kind == 'step':
            pc += 4
        elif kind == 'ecall':
            trap = 8 + (priv > 0)
        elif kind == 'illegal':
            trap = 2
        elif kind == 'irq':
            if priv < 3 or mie:
                trap = (1 << 31) | ev[1]
        elif kind == 'mret':
            mie = mpie
            mpie = 1
            priv = mpp
            mpp = 0
            pc = mepc
        if trap is not None:
            mepc = pc
            mcause = trap
            mpie = mie
            mie = 0
            mpp = priv
            priv = 3
            base = mtvec & ~3
            pc = base + 4 * (trap & 0x7FFFFFFF) if (mtvec & 3) == 1 and trap >> 31 else base
        log.append([pc, priv, mie, mpie, mpp, mcause, mepc])
    return log
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('user ecall and return', [1028, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4354, [['ecall'], ['mret']]], [[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1032, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1036, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1036], [4100, 3, 0, 1, 0, 8, 1036], [1036, 0, 1, 1, 0, 8, 1036]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4610, [['ecall'], ['mret']]], [[4608, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1036, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1040, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1040], [4100, 3, 0, 1, 0, 8, 1040], [1040, 0, 1, 1, 0, 8, 1040]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4866, [['ecall'], ['mret']]], [[4864, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1040, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1044, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1044], [4100, 3, 0, 1, 0, 8, 1044], [1044, 0, 1, 1, 0, 8, 1044]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5122, [['ecall'], ['mret']]], [[5120, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1044, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1048, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1048], [4100, 3, 0, 1, 0, 8, 1048], [1048, 0, 1, 1, 0, 8, 1048]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5378, [['ecall'], ['mret']]], [[5376, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096], [4116, 0, 1, 1, 0, 2, 4096]])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
user ecall and return	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]`	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]`	Passed
supervisor and machine ecall	`[[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 9, 4096], [4096, 3, 0, 1, 0, 9, 4096], [4096, 0, 1, 1, 0, 9, 4096]]`	`[[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]`	Failed
supervisor interrupt with mie clear	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	Passed
machine interrupt masked then enabled	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	Passed
machine interrupt enabled saves mie	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	Passed
vectored mode exceptions go to base	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]`	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]`	Passed
reserved mode bits masked	`[[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]`	`[[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]`	Passed
nested trap overwrites mpp	`[[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	`[[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	Passed

SHA-256 / a2efca353b844c48d2c33d0566ffa0bac899b581b4061659a328aae5bb89d496

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(*args):
    pc, priv, mie, mtvec, events = args
    mpie = mpp = mcause = mepc = 0
    log = []
    for ev in events:
        kind = ev[0]
        trap = None
        if kind == 'step':
            pc += 4
        elif kind == 'ecall':
            trap = 8 + priv
        elif kind == 'illegal':
            trap = 2
        elif kind == 'irq':
            if priv < 3 or mie:
                trap = (1 << 31) | ev[1]
        elif kind == 'mret':
            mie = mpie
            mpie = 1
            priv = mpp
            mpp = 0
            pc = mepc
        if trap is not None:
            mepc = pc
            mcause = trap
            mpie = mie
            mie = 0
            mpp = priv
            priv = 3
            base = mtvec & ~3
            pc = base + 4 * (trap & 0x7FFFFFFF) if (mtvec & 3) == 1 and trap >> 31 else base
        log.append([pc, priv, mie, mpie, mpp, mcause, mepc])
    return log
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[('user ecall and return', [1028, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4354, [['ecall'], ['mret']]], [[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1032, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1036, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1036], [4100, 3, 0, 1, 0, 8, 1036], [1036, 0, 1, 1, 0, 8, 1036]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4610, [['ecall'], ['mret']]], [[4608, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1036, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1040, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1040], [4100, 3, 0, 1, 0, 8, 1040], [1040, 0, 1, 1, 0, 8, 1040]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 4866, [['ecall'], ['mret']]], [[4864, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1040, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1044, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1044], [4100, 3, 0, 1, 0, 8, 1044], [1044, 0, 1, 1, 0, 8, 1044]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 11]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4140, 3, 0, 0, 0, 2147483659, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5122, [['ecall'], ['mret']]], [[5120, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096]])], [('user ecall and return', [1044, 0, 1, 4096, [['step'], ['ecall'], ['step'], ['mret']]], [[1048, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1048], [4100, 3, 0, 1, 0, 8, 1048], [1048, 0, 1, 1, 0, 8, 1048]]), ('supervisor and machine ecall', [1024, 1, 0, 4096, [['ecall'], ['ecall'], ['mret'], ['mret']]], [[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]), ('supervisor interrupt with mie clear', [1280, 1, 0, 4097, [['irq', 7], ['mret'], ['step']]], [[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]), ('machine interrupt masked then enabled', [1536, 3, 0, 4097, [['irq', 3], ['step'], ['mret'], ['irq', 10]]], [[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]), ('machine interrupt enabled saves mie', [1792, 3, 1, 8192, [['irq', 7], ['mret'], ['step']]], [[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]), ('vectored mode exceptions go to base', [2048, 0, 1, 12289, [['illegal'], ['mret'], ['ecall']]], [[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]), ('reserved mode bits masked', [2560, 1, 1, 5378, [['ecall'], ['mret']]], [[5376, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]), ('nested trap overwrites mpp', [2304, 0, 1, 4096, [['ecall'], ['illegal'], ['mret'], ['mret'], ['step'], ['step'], ['step'], ['step'], ['step']]], [[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096], [4104, 0, 1, 1, 0, 2, 4096], [4108, 0, 1, 1, 0, 2, 4096], [4112, 0, 1, 1, 0, 2, 4096], [4116, 0, 1, 1, 0, 2, 4096]])]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
user ecall and return	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]`	`[[1032, 0, 1, 0, 0, 0, 0], [4096, 3, 0, 1, 0, 8, 1032], [4100, 3, 0, 1, 0, 8, 1032], [1032, 0, 1, 1, 0, 8, 1032]]`	Passed
supervisor and machine ecall	`[[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]`	`[[4096, 3, 0, 0, 1, 9, 1024], [4096, 3, 0, 0, 3, 11, 4096], [4096, 3, 0, 1, 0, 11, 4096], [4096, 0, 1, 1, 0, 11, 4096]]`	Passed
supervisor interrupt with mie clear	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	`[[4124, 3, 0, 0, 1, 2147483655, 1280], [1280, 1, 0, 1, 0, 2147483655, 1280], [1284, 1, 0, 1, 0, 2147483655, 1280]]`	Passed
machine interrupt masked then enabled	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	`[[1536, 3, 0, 0, 0, 0, 0], [1540, 3, 0, 0, 0, 0, 0], [0, 0, 0, 1, 0, 0, 0], [4136, 3, 0, 0, 0, 2147483658, 0]]`	Passed
machine interrupt enabled saves mie	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	`[[8192, 3, 0, 1, 3, 2147483655, 1792], [1792, 3, 1, 1, 0, 2147483655, 1792], [1796, 3, 1, 1, 0, 2147483655, 1792]]`	Passed
vectored mode exceptions go to base	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]`	`[[12288, 3, 0, 1, 0, 2, 2048], [2048, 0, 1, 1, 0, 2, 2048], [12288, 3, 0, 1, 0, 8, 2048]]`	Passed
reserved mode bits masked	`[[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]`	`[[4352, 3, 0, 1, 1, 9, 2560], [2560, 1, 1, 1, 0, 9, 2560]]`	Passed
nested trap overwrites mpp	`[[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	`[[4096, 3, 0, 1, 0, 8, 2304], [4096, 3, 0, 0, 3, 2, 4096], [4096, 3, 0, 1, 0, 2, 4096], [4096, 0, 1, 1, 0, 2, 4096], [4100, 0, 1, 1, 0, 2, 4096]]`	Passed

SHA-256 / 0b2a873f8a03df16cb855a93f29fc263ffe64e9c097843541279d90834d43f1d

Verification & scope

A deterministic bounded teaching model of one emulator rule; the instruction semantics are a stipulated contract inspired by common ISAs and are not a claim of cycle-exact or architectural conformance. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:51:20.447568+00:00.

Case digest / ed092b89860a726f73ae59dd728e33eac327523b6f2260053ae33b60b595508a