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Shared Functions.Common Pseudocode

Library pseudocode for shared/functions/common/ASR

// ASR()
// =====

bits(N) ASR(bits(N) x, integer shift)
    assert shift >= 0;
    if shift == 0 then
        result = x;
    else
        (result, -) = ASR_C(x, shift);
    return result;

Library pseudocode for shared/functions/common/ASR_C

// ASR_C()
// =======

(bits(N), bit) ASR_C(bits(N) x, integer shift)
    assert shift > 0;
    extended_x = SignExtend(x, shift+N);
    result = extended_x<shift+N-1:shift>;
    carry_out = extended_x<shift-1>;
    return (result, carry_out);

Library pseudocode for shared/functions/common/Abs

// Abs()
// =====

integer Abs(integer x)
    return if x >= 0 then x else -x;

// Abs()
// =====

real Abs(real x)
    return if x >= 0.0 then x else -x;

Library pseudocode for shared/functions/common/Align

// Align()
// =======

integer Align(integer x, integer y)
    return y * (x DIV y);

// Align()
// =======

bits(N) Align(bits(N) x, integer y)
    return Align(UInt(x), y)<N-1:0>;

Library pseudocode for shared/functions/common/BitCount

// BitCount()
// ==========

integer BitCount(bits(N) x)
    integer result = 0;
    for i = 0 to N-1
        if x<i> == '1' then
            result = result + 1;
    return result;

Library pseudocode for shared/functions/common/CountLeadingSignBits

// CountLeadingSignBits()
// ======================

integer CountLeadingSignBits(bits(N) x)
    return CountLeadingZeroBits(x<N-1:1> EOR x<N-2:0>);

Library pseudocode for shared/functions/common/CountLeadingZeroBits

// CountLeadingZeroBits()
// ======================

integer CountLeadingZeroBits(bits(N) x)
    return N - (HighestSetBit(x) + 1);

Library pseudocode for shared/functions/common/Elem

// Elem[] - non-assignment form
// ============================

bits(size) Elem[bits(N) vector, integer e, integer size]
    assert e >= 0 && (e+1)*size <= N;
    return vector<e*size+size-1 : e*size>;

// Elem[] - non-assignment form
// ============================

bits(size) Elem[bits(N) vector, integer e]
    return Elem[vector, e, size];

// Elem[] - assignment form
// ========================

Elem[bits(N) &vector, integer e, integer size] = bits(size) value
    assert e >= 0 && (e+1)*size <= N;
    vector<(e+1)*size-1:e*size> = value;
    return;

// Elem[] - assignment form
// ========================

Elem[bits(N) &vector, integer e] = bits(size) value
    Elem[vector, e, size] = value;
    return;

Library pseudocode for shared/functions/common/Extend

// Extend()
// ========

bits(N) Extend(bits(M) x, integer N, boolean unsigned)
    return if unsigned then ZeroExtend(x, N) else SignExtend(x, N);

// Extend()
// ========

bits(N) Extend(bits(M) x, boolean unsigned)
    return Extend(x, N, unsigned);

Library pseudocode for shared/functions/common/HighestSetBit

// HighestSetBit()
// ===============

integer HighestSetBit(bits(N) x)
    for i = N-1 downto 0
        if x<i> == '1' then return i;
    return -1;

Library pseudocode for shared/functions/common/Int

// Int()
// =====

integer Int(bits(N) x, boolean unsigned)
    result = if unsigned then UInt(x) else SInt(x);
    return result;

Library pseudocode for shared/functions/common/IsOnes

// IsOnes()
// ========

boolean IsOnes(bits(N) x)
    return x == Ones(N);

Library pseudocode for shared/functions/common/IsZero

// IsZero()
// ========

boolean IsZero(bits(N) x)
    return x == Zeros(N);

Library pseudocode for shared/functions/common/IsZeroBit

// IsZeroBit()
// ===========

bit IsZeroBit(bits(N) x)
    return if IsZero(x) then '1' else '0';

Library pseudocode for shared/functions/common/LSL

// LSL()
// =====

bits(N) LSL(bits(N) x, integer shift)
    assert shift >= 0;
    if shift == 0 then
        result = x;
    else
        (result, -) = LSL_C(x, shift);
    return result;

Library pseudocode for shared/functions/common/LSL_C

// LSL_C()
// =======

(bits(N), bit) LSL_C(bits(N) x, integer shift)
    assert shift > 0;
    extended_x = x : Zeros(shift);
    result = extended_x<N-1:0>;
    carry_out = extended_x<N>;
    return (result, carry_out);

Library pseudocode for shared/functions/common/LSR

// LSR()
// =====

bits(N) LSR(bits(N) x, integer shift)
    assert shift >= 0;
    if shift == 0 then
        result = x;
    else
        (result, -) = LSR_C(x, shift);
    return result;

Library pseudocode for shared/functions/common/LSR_C

// LSR_C()
// =======

(bits(N), bit) LSR_C(bits(N) x, integer shift)
    assert shift > 0;
    extended_x = ZeroExtend(x, shift+N);
    result = extended_x<shift+N-1:shift>;
    carry_out = extended_x<shift-1>;
    return (result, carry_out);

Library pseudocode for shared/functions/common/LowestSetBit

// LowestSetBit()
// ==============

integer LowestSetBit(bits(N) x)
    for i = 0 to N-1
        if x<i> == '1' then return i;
    return N;

Library pseudocode for shared/functions/common/Max

// Max()
// =====

integer Max(integer a, integer b)
    return if a >= b then a else b;

// Max()
// =====

real Max(real a, real b)
    return if a >= b then a else b;

Library pseudocode for shared/functions/common/Min

// Min()
// =====

integer Min(integer a, integer b)
    return if a <= b then a else b;

// Min()
// =====

real Min(real a, real b)
    return if a <= b then a else b;

Library pseudocode for shared/functions/common/Ones

// Ones()
// ======

bits(N) Ones(integer N)
    return Replicate('1',N);

// Ones()
// ======

bits(N) Ones()
    return Ones(N);

Library pseudocode for shared/functions/common/ROR

// ROR()
// =====

bits(N) ROR(bits(N) x, integer shift)
    assert shift >= 0;
    if shift == 0 then
        result = x;
    else
        (result, -) = ROR_C(x, shift);
    return result;

Library pseudocode for shared/functions/common/ROR_C

// ROR_C()
// =======

(bits(N), bit) ROR_C(bits(N) x, integer shift)
    assert shift != 0;
    m = shift MOD N;
    result = LSR(x,m) OR LSL(x,N-m);
    carry_out = result<N-1>;
    return (result, carry_out);

Library pseudocode for shared/functions/common/Replicate

// Replicate()
// ===========

bits(N) Replicate(bits(M) x)
    assert N MOD M == 0;
    return Replicate(x, N DIV M);

bits(M*N) Replicate(bits(M) x, integer N);

Library pseudocode for shared/functions/common/RoundDown

integer RoundDown(real x);

Library pseudocode for shared/functions/common/RoundTowardsZero

// RoundTowardsZero()
// ==================

integer RoundTowardsZero(real x)
    return if x == 0.0 then 0 else if x >= 0.0 then RoundDown(x) else RoundUp(x);

Library pseudocode for shared/functions/common/RoundUp

integer RoundUp(real x);

Library pseudocode for shared/functions/common/SInt

// SInt()
// ======

integer SInt(bits(N) x)
    result = 0;
    for i = 0 to N-1
        if x<i> == '1' then result = result + 2^i;
    if x<N-1> == '1' then result = result - 2^N;
    return result;

Library pseudocode for shared/functions/common/SignExtend

// SignExtend()
// ============

bits(N) SignExtend(bits(M) x, integer N)
    assert N >= M;
    return Replicate(x<M-1>, N-M) : x;

// SignExtend()
// ============

bits(N) SignExtend(bits(M) x)
    return SignExtend(x, N);

Library pseudocode for shared/functions/common/UInt

// UInt()
// ======

integer UInt(bits(N) x)
    result = 0;
    for i = 0 to N-1
        if x<i> == '1' then result = result + 2^i;
    return result;

Library pseudocode for shared/functions/common/ZeroExtend

// ZeroExtend()
// ============

bits(N) ZeroExtend(bits(M) x, integer N)
    assert N >= M;
    return Zeros(N-M) : x;

// ZeroExtend()
// ============

bits(N) ZeroExtend(bits(M) x)
    return ZeroExtend(x, N);

Library pseudocode for shared/functions/common/Zeros

// Zeros()
// =======

bits(N) Zeros(integer N)
    return Replicate('0',N);

// Zeros()
// =======

bits(N) Zeros()
    return Zeros(N);
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