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Precalculate mask in simulation of ALTRO chip #11

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Precalculate mask in simulation of ALTRO chip #11

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dcf34b1
Precalculate masks for Altro::mask(...) routine
plexoos Apr 2, 2020
2cff8b0
Precalculate masks for Altro::maskandshift(...) routine
plexoos Apr 2, 2020
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28 changes: 14 additions & 14 deletions src/altro.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -406,13 +406,13 @@ int Altro::multiply36(int P, int N)
long long temp = 0;
long long AX = 0;
temp = (long long)P * (long long)N;
AX = (( mask(temp, 35, 18) + ((long long)(-P) << 18) ) + mask(temp, 17, 0));
AX = (( mask_35_18(temp) + ((long long)(-P) << 18) ) + mask_17_0(temp));

if ( maskandshift(N, 17, 17) == 1) {
retval = ((maskandshift(AX, 35, 35) << 17) + maskandshift(AX, 32, 16));
if ( maskandshift_17_17(N) == 1) {
retval = (maskandshift_35_35(AX) << 17) + maskandshift_32_16(AX);
}
else {
retval = maskandshift(temp, 32, 16);
retval = maskandshift_32_16(temp);
}

return retval;
Expand Down Expand Up @@ -450,19 +450,19 @@ void Altro::TailCancellationFilter_FixedPoint(int K1, int K2, int K3, int L1, in
din = channelShort[i];

din = (din << 2);
c1n = mask( (mask(din, 17, 0) + multiply36(K1, mask(c1o, 17, 0)) ), 17, 0);
d1 = mask( (mask(c1n, 17, 0) - multiply36(L1, mask(c1o, 17, 0)) ), 17, 0);
c1n = mask_17_0( (mask_17_0(din) + multiply36(K1, mask_17_0(c1o)) ));
d1 = mask_17_0( (mask_17_0(c1n) - multiply36(L1, mask_17_0(c1o)) ));
//d1 = mask( (mask(c1n,17,0) + mask(~multiply36(L1,mask(c1o,17,0))+1,17,0) ) ,17,0);

c2n = mask( (mask(d1, 17, 0) + multiply36(K2, mask(c2o, 17, 0)) ), 17, 0);
d2 = mask( (mask(c2n, 17, 0) - multiply36(L2, mask(c2o, 17, 0)) ), 17, 0);
c2n = mask_17_0( (mask_17_0(d1) + multiply36(K2, mask_17_0(c2o)) ));
d2 = mask_17_0( (mask_17_0(c2n) - multiply36(L2, mask_17_0(c2o)) ));
//d2 = mask( (mask(c2n,17,0) + mask(~multiply36(L2,mask(c2o,17,0))+1,17,0) ) ,17,0);

c3n = mask( (mask(d2, 17, 0) + multiply36(K3, mask(c3o, 17, 0)) ), 17, 0);
dout = mask( (mask(c3n, 17, 0) - multiply36(L3, mask(c3o, 17, 0)) ), 17, 0);
c3n = mask_17_0( (mask_17_0(d2) + multiply36(K3, mask_17_0(c3o)) ));
dout = mask_17_0( (mask_17_0(c3n) - multiply36(L3, mask_17_0(c3o)) ));
//dout = mask( (mask(c3n,17,0) + mask(~multiply36(L3,mask(c3o,17,0))+1,17,0) ) ,17,0);

if ( (maskandshift(dout, 2, 2) == 1) || (maskandshift(dout, 1, 1) == 1)) {
if ( maskandshift_2_2(dout) == 1 || maskandshift_1_1(dout) == 1) {
bit = 1;
}
else {
Expand All @@ -471,12 +471,12 @@ void Altro::TailCancellationFilter_FixedPoint(int K1, int K2, int K3, int L1, in

dout = ((dout >> 3) << 1) + bit;

if (maskandshift(dout, 15, 15) == 1) {
if (maskandshift_15_15(dout) == 1) {
//is needed to get the correct coding when getting negative results
dout = -mask((-mask(dout, 9, 0)), 9, 0);
dout = -mask_9_0(-mask_9_0(dout));
}
else {
dout = mask(dout, 9, 0);
dout = mask_9_0(dout);
}

channelShort[i] = (short) dout;
Expand Down
31 changes: 31 additions & 0 deletions src/altro.h
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Original file line number Diff line number Diff line change
Expand Up @@ -114,5 +114,36 @@ class Altro
short GetKeepChannel(int i);
int multiply36(int P, int N);
long long mask(long long in, int left, int right);

/// Precalculated masks based on the algorithm implemented in
/// `Altro::mask(long long, int left, int right)` and invoked with fixed
/// values for the `left` and `right` arguments.
///@{
/// left=9, right=0
long long mask_9_0(long long in) { return in & 0b000000000000000000000000001111111111; }
/// left=17, right=0
long long mask_17_0(long long in) { return in & 0b000000000000000000111111111111111111; }
/// left=35, right=18
long long mask_35_18(long long in) { return in & 0b111111111111111111000000000000000000; }
///@}

long long maskandshift(long long in, int left, int right);

/// Precalculated masks based on the algorithm implemented in
/// `Altro::maskandshift(long long, int left, int right)` and invoked with
/// fixed values for the `left` and `right` arguments.
///@{
/// left=1, right=1
long long maskandshift_1_1(long long in) { return (in >> 1) & 0b000000000000000001; }
/// left=2, right=2
long long maskandshift_2_2(long long in) { return (in >> 2) & 0b000000000000000001; }
/// left=15, right=15
long long maskandshift_15_15(long long in) { return (in >> 15) & 0b000000000000000001; }
/// left=17, right=17
long long maskandshift_17_17(long long in) { return (in >> 17) & 0b000000000000000001; }
/// left=35, right=35
long long maskandshift_35_35(long long in) { return (in >> 35) & 0b000000000000000001; }
/// left=32, right=16
long long maskandshift_32_16(long long in) { return (in >> 16) & 0b011111111111111111; }
///@}
};