def execute_bcond(s, inst):
"""
B<COND>:
IF (Passed)<COND>)) then
PC = PC + (SignExtend(SIMM) << 1)
BL:
LR = next PC;
PC = PC + (SignExtend(SIMM) << 1)
"""
if is16bit:
inst.bits &= 0xFFFF
cond = inst.cond
imm = inst.bcond_imm
if cond == 0 and imm == 0:
raise RuntimeError(
(
"Epiphany simulator caught infinite loop at runtime. "
+ "Instruction at pc=%s is attempting to "
+ "branch unconditionally to itself."
)
% hex(s.pc)
)
if cond == 0b1111: # Branch and link (BL).
s.rf[epiphany.isa.reg_map["LR"]] = s.pc + (2 if is16bit else 4)
if condition_passed(s, cond):
offset = (signed(sext_8(imm)) << 1) if is16bit else (signed(sext_24(imm)) << 1)
s.pc = trim_32(s.pc + offset)
else:
s.pc += 2 if is16bit else 4
s.debug_flags()
def execute_movcond(s, inst):
"""
IF (Passed) <COND> then
RD = RN
"""
if is16bit:
inst.bits &= 0xffff
rd = inst.rd
rn = inst.rn
if condition_passed(s, inst.cond):
s.rf[rd] = s.rf[rn]
s.debug_flags()
s.pc += 2 if is16bit else 4
def test_condition_passed():
state = new_state(AZ=1)
assert condition_passed(state, 0b0000)
state.AZ = 0
assert condition_passed(state, 0b0001)
state.AZ = 0
state.AC = 1
assert condition_passed(state, 0b0010)
state.AC = 1
assert condition_passed(state, 0b0011)
state.AZ = 1
state.AC = 0
assert condition_passed(state, 0b0100)
state.AC = 0
assert condition_passed(state, 0b0101)
state.AZ = 0
state.AV = state.AN = 2
assert condition_passed(state, 0b0110)
state.AZ = 1
state.AV = state.AN = 3
assert condition_passed(state, 0b0111)
state.AV = 4
state.AN = 3
assert condition_passed(state, 0b1000)
state.AZ = 1
state.AV = 3
state.AN = 4
assert condition_passed(state, 0b1001)
state.BZ = 1
assert condition_passed(state, 0b1010)
state.BZ = 0
assert condition_passed(state, 0b1011)
state.BN = 1
state.BZ = 0
assert condition_passed(state, 0b1100)
state.BN = 1
state.BZ = 1
assert condition_passed(state, 0b1101)
assert condition_passed(state, 0b1110)
assert condition_passed(state, 0b1111)
with pytest.raises(ValueError):
condition_passed(state, 0b11111)
