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alu.py
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alu.py
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from peak import Peak, name_outputs, family_closure, Const
from peak.mapper.utils import rebind_type
from .common import DATAWIDTH, BFloat16_fc
from hwtypes.adt import Enum
from hwtypes import BitVector, Bit as BitPy
class ALU_t(Enum):
Adc = 0
Sbc = 1
Abs = 2
Sel = 3
Mult0 = 4
Mult1 = 5
Mult2 = 6
SHR = 7
SHL = 8
Or = 9
And = 10
XOr = 11
MULADD = 12
MULSUB = 13
TAA = 14
TAS = 15
TSA = 16
TSS = 17
CROP = 18
MULSHR = 19
class Signed_t(Enum):
unsigned = 0
signed = 1
def overflow(a, b, res):
msb_a = a[-1]
msb_b = b[-1]
N = res[-1]
return (msb_a & msb_b & ~N) | (~msb_a & ~msb_b & N)
@family_closure
def ALU_fc(family):
Data = family.BitVector[DATAWIDTH]
Bit = family.Bit
SInt = family.Signed
SData = SInt[DATAWIDTH]
UInt = family.Unsigned
UData = UInt[DATAWIDTH]
UData32 = UInt[32]
DataPy = BitVector[DATAWIDTH]
@family.assemble(locals(), globals(), set_port_names=True)
class ALU(Peak):
@name_outputs(res=Data, res_p=Bit, Z=Bit, N=Bit, C=Bit, V=Bit)
def __call__(
self,
alu: Const(ALU_t),
signed_: Const(Signed_t),
a: DataPy,
b: DataPy,
c: DataPy,
d: BitPy,
) -> (DataPy, BitPy, BitPy, BitPy, BitPy, BitPy):
# MUL
if signed_ == Signed_t.signed:
mula = UData32(SData(a).sext(16))
mulb = UData32(SData(b).sext(16))
else: # signed_ == Signed_t.unsigned:
mula = UData(a).zext(16)
mulb = UData(b).zext(16)
mul = mula * mulb
# LTE and min
if signed_ == Signed_t.signed:
lte_pred = SData(a) <= SData(b)
else:
lte_pred = UData(a) <= UData(b)
min_ab = lte_pred.ite(a, b)
# CROP (min -> max)
if alu == ALU_t.CROP:
max_in0 = min_ab
else:
max_in0 = b
# GTE and min
if signed_ == Signed_t.signed:
gte_pred = SData(max_in0) >= SData(c)
else:
gte_pred = UData(max_in0) >= UData(c)
max_bc = gte_pred.ite(max_in0, c)
# mulshift
if alu == ALU_t.MULSHR:
shr_in0 = mul[:16]
else:
shr_in0 = a
if signed_ == Signed_t.signed:
shr = Data(SData(shr_in0) >> SData(c))
else: # signed_ == Signed_t.unsigned:
shr = Data(UData(shr_in0) >> UData(c))
if (alu == ALU_t.Sbc) | (alu == ALU_t.TSA) | (alu == ALU_t.TSS):
b = ~b
Cin = d
# factor out comman add
adder_res, adder_C = UData(a).adc(UData(b), Cin)
# second adder
# 1st input
if (
(alu == ALU_t.TAA)
| (alu == ALU_t.TAS)
| (alu == ALU_t.TSA)
| (alu == ALU_t.TSS)
):
adder2_in0 = adder_res
else:
adder2_in0 = mul[:16]
# 2nd input
if (alu == ALU_t.MULSUB) | (alu == ALU_t.TAS) | (alu == ALU_t.TSS):
adder2_in1 = ~c
Cin2 = Bit(1)
else:
adder2_in1 = c
Cin2 = Bit(0)
adder2_res, adder2_C = UData(adder2_in0).adc(adder2_in1, Cin2)
C = Bit(0)
V = Bit(0)
if (alu == ALU_t.Adc) | (alu == ALU_t.Sbc):
res, C = adder_res, adder_C
V = overflow(a, b, res)
res_p = C
elif alu == ALU_t.Mult0:
res, C, V = mul[:16], Bit(0), Bit(0)
res_p = C
elif alu == ALU_t.Mult1:
res, C, V = mul[8:24], Bit(0), Bit(0)
res_p = C
elif alu == ALU_t.Mult2:
res, C, V = mul[16:32], Bit(0), Bit(0)
res_p = C
elif alu == ALU_t.Abs:
abs_pred = SData(a) >= SData(0)
res, res_p = abs_pred.ite(a, UInt[16](-SInt[16](a))), Bit(a[-1])
elif alu == ALU_t.Sel:
res, res_p = d.ite(a, b), Bit(0)
elif alu == ALU_t.And:
res, res_p = a & b, Bit(0)
elif alu == ALU_t.Or:
res, res_p = a | b, Bit(0)
elif alu == ALU_t.XOr:
res, res_p = a ^ b, Bit(0)
elif alu == ALU_t.SHR:
res, res_p = shr, Bit(0)
elif alu == ALU_t.SHL:
res, res_p = a << b, Bit(0)
elif (
(alu == ALU_t.MULADD)
| (alu == ALU_t.MULSUB)
| (alu == ALU_t.TAA)
| (alu == ALU_t.TSA)
| (alu == ALU_t.TAS)
| (alu == ALU_t.TSS)
):
res, res_p = adder2_res, Bit(0)
elif alu == ALU_t.CROP:
res, res_p = max_bc, Bit(0)
else: # (alu == ALU_t.MULSHR):
res, res_p = shr, Bit(0)
N = Bit(res[-1])
Z = res == SData(0)
return res, res_p, Z, N, C, V
return ALU