/*
* yosys -- Yosys Open SYnthesis Suite
*
- * Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
+ * Copyright (C) 2012 Claire Xenia Wolf <claire@yosyshq.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
return result;
}
-static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, int direction, int result_len)
+// Shift `arg1` by `arg2` bits.
+// If `direction` is +1, `arg1` is shifted right by `arg2` bits; if `direction` is -1, `arg1` is shifted left by `arg2` bits.
+// If `signed2` is true, `arg2` is interpreted as a signed integer; a negative `arg2` will cause a shift in the opposite direction.
+// Any required bits outside the bounds of `arg1` are padded with `vacant_bits` unless `sign_ext` is true, in which case any bits outside the left
+// bounds are filled with the leftmost bit of `arg1` (arithmetic shift).
+static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, bool signed2, int direction, int result_len, RTLIL::State vacant_bits = RTLIL::State::S0)
{
int undef_bit_pos = -1;
- BigInteger offset = const2big(arg2, false, undef_bit_pos) * direction;
+ BigInteger offset = const2big(arg2, signed2, undef_bit_pos) * direction;
if (result_len < 0)
result_len = arg1.bits.size();
for (int i = 0; i < result_len; i++) {
BigInteger pos = BigInteger(i) + offset;
if (pos < 0)
- result.bits[i] = RTLIL::State::S0;
- else if (pos >= BigInteger(arg1.bits.size()))
- result.bits[i] = sign_ext ? arg1.bits.back() : RTLIL::State::S0;
+ result.bits[i] = vacant_bits;
+ else if (pos >= BigInteger(int(arg1.bits.size())))
+ result.bits[i] = sign_ext ? arg1.bits.back() : vacant_bits;
else
result.bits[i] = arg1.bits[pos.toInt()];
}
{
RTLIL::Const arg1_ext = arg1;
extend_u0(arg1_ext, result_len, signed1);
- return const_shift_worker(arg1_ext, arg2, false, -1, result_len);
+ return const_shift_worker(arg1_ext, arg2, false, false, -1, result_len);
}
RTLIL::Const RTLIL::const_shr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
{
RTLIL::Const arg1_ext = arg1;
extend_u0(arg1_ext, max(result_len, GetSize(arg1)), signed1);
- return const_shift_worker(arg1_ext, arg2, false, +1, result_len);
+ return const_shift_worker(arg1_ext, arg2, false, false, +1, result_len);
}
-RTLIL::Const RTLIL::const_sshl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+RTLIL::Const RTLIL::const_sshl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
{
- if (!signed1)
- return const_shl(arg1, arg2, signed1, signed2, result_len);
- return const_shift_worker(arg1, arg2, true, -1, result_len);
+ return const_shift_worker(arg1, arg2, signed1, false, -1, result_len);
}
-RTLIL::Const RTLIL::const_sshr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+RTLIL::Const RTLIL::const_sshr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
{
- if (!signed1)
- return const_shr(arg1, arg2, signed1, signed2, result_len);
- return const_shift_worker(arg1, arg2, true, +1, result_len);
-}
-
-static RTLIL::Const const_shift_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool, bool signed2, int result_len, RTLIL::State other_bits)
-{
- int undef_bit_pos = -1;
- BigInteger offset = const2big(arg2, signed2, undef_bit_pos);
-
- if (result_len < 0)
- result_len = arg1.bits.size();
-
- RTLIL::Const result(RTLIL::State::Sx, result_len);
- if (undef_bit_pos >= 0)
- return result;
-
- for (int i = 0; i < result_len; i++) {
- BigInteger pos = BigInteger(i) + offset;
- if (pos < 0 || pos >= BigInteger(arg1.bits.size()))
- result.bits[i] = other_bits;
- else
- result.bits[i] = arg1.bits[pos.toInt()];
- }
-
- return result;
+ return const_shift_worker(arg1, arg2, signed1, false, +1, result_len);
}
RTLIL::Const RTLIL::const_shift(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
- return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::S0);
+ RTLIL::Const arg1_ext = arg1;
+ extend_u0(arg1_ext, max(result_len, GetSize(arg1)), signed1);
+ return const_shift_worker(arg1_ext, arg2, false, signed2, +1, result_len);
}
-RTLIL::Const RTLIL::const_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+RTLIL::Const RTLIL::const_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool, bool signed2, int result_len)
{
- return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::Sx);
+ return const_shift_worker(arg1, arg2, false, signed2, +1, result_len, RTLIL::State::Sx);
}
RTLIL::Const RTLIL::const_lt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
+// truncating division
RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
return big2const(result_neg ? -(a / b) : (a / b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
+// truncating modulo
RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
return big2const(result_neg ? -(a % b) : (a % b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
}
+RTLIL::Const RTLIL::const_divfloor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+{
+ int undef_bit_pos = -1;
+ BigInteger a = const2big(arg1, signed1, undef_bit_pos);
+ BigInteger b = const2big(arg2, signed2, undef_bit_pos);
+ if (b.isZero())
+ return RTLIL::Const(RTLIL::State::Sx, result_len);
+
+ bool result_pos = (a.getSign() == BigInteger::negative) == (b.getSign() == BigInteger::negative);
+ a = a.getSign() == BigInteger::negative ? -a : a;
+ b = b.getSign() == BigInteger::negative ? -b : b;
+ BigInteger result;
+
+ if (result_pos || a == 0) {
+ result = a / b;
+ } else {
+ // bigint division with negative numbers is wonky, make sure we only negate at the very end
+ result = -((a + b - 1) / b);
+ }
+ return big2const(result, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
+}
+
+RTLIL::Const RTLIL::const_modfloor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
+{
+ int undef_bit_pos = -1;
+ BigInteger a = const2big(arg1, signed1, undef_bit_pos);
+ BigInteger b = const2big(arg2, signed2, undef_bit_pos);
+ if (b.isZero())
+ return RTLIL::Const(RTLIL::State::Sx, result_len);
+
+ BigInteger::Sign a_sign = a.getSign();
+ BigInteger::Sign b_sign = b.getSign();
+ a = a_sign == BigInteger::negative ? -a : a;
+ b = b_sign == BigInteger::negative ? -b : b;
+ BigInteger truncated = a_sign == BigInteger::negative ? -(a % b) : (a % b);
+ BigInteger modulo;
+
+ if (truncated == 0 || (a_sign == b_sign)) {
+ modulo = truncated;
+ } else {
+ modulo = b_sign == BigInteger::negative ? truncated - b : truncated + b;
+ }
+ return big2const(modulo, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
+}
+
RTLIL::Const RTLIL::const_pow(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
{
int undef_bit_pos = -1;
projects / yosys.git / blobdiff