X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=kernel%2Fcalc.cc;h=1e6410f7dbf0e90de971b99523f363da04c740bc;hb=1667ad658b3aefd3b5418dace6403d3990029fb9;hp=da03f61642b131b8557d66485627514d3ed74da7;hpb=b9cb483f3e2a498ee75a422e09164a920918362b;p=yosys.git

diff --git a/kernel/calc.cc b/kernel/calc.cc
index da03f6164..1e6410f7d 100644
--- a/kernel/calc.cc
+++ b/kernel/calc.cc
@@ -1,12 +1,12 @@
 /*
  *  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
  *  copyright notice and this permission notice appear in all copies.
- *  
+ *
  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
@@ -26,19 +26,6 @@
 
 YOSYS_NAMESPACE_BEGIN
 
-static void extend(RTLIL::Const &arg, int width, bool is_signed)
-{
-	RTLIL::State padding = RTLIL::State::S0;
-
-	if (arg.bits.size() > 0 && (is_signed || arg.bits.back() > RTLIL::State::S1))
-		padding = arg.bits.back();
-
-	while (int(arg.bits.size()) < width)
-		arg.bits.push_back(padding);
-
-	arg.bits.resize(width);
-}
-
 static void extend_u0(RTLIL::Const &arg, int width, bool is_signed)
 {
 	RTLIL::State padding = RTLIL::State::S0;
@@ -54,21 +41,28 @@ static void extend_u0(RTLIL::Const &arg, int width, bool is_signed)
 
 static BigInteger const2big(const RTLIL::Const &val, bool as_signed, int &undef_bit_pos)
 {
-	BigInteger result = 0, this_bit = 1;
-	for (size_t i = 0; i < val.bits.size(); i++) {
-		if (val.bits[i] == RTLIL::State::S1) {
-			if (as_signed && i+1 == val.bits.size())
-				result -= this_bit;
-			else
-				result += this_bit;
-		}
-		else if (val.bits[i] != RTLIL::State::S0) {
-			if (undef_bit_pos < 0)
-				undef_bit_pos = i;
-		}
-		this_bit *= 2;
+	BigUnsigned mag;
+
+	BigInteger::Sign sign = BigInteger::positive;
+	State inv_sign_bit = RTLIL::State::S1;
+	size_t num_bits = val.bits.size();
+
+	if (as_signed && num_bits && val.bits[num_bits-1] == RTLIL::State::S1) {
+		inv_sign_bit = RTLIL::State::S0;
+		sign = BigInteger::negative;
+		num_bits--;
 	}
-	return result;
+
+	for (size_t i = 0; i < num_bits; i++)
+		if (val.bits[i] == RTLIL::State::S0 || val.bits[i] == RTLIL::State::S1)
+			mag.setBit(i, val.bits[i] == inv_sign_bit);
+		else if (undef_bit_pos < 0)
+			undef_bit_pos = i;
+
+	if (sign == BigInteger::negative)
+		mag += 1;
+
+	return BigInteger(mag, sign);
 }
 
 static RTLIL::Const big2const(const BigInteger &val, int result_len, int undef_bit_pos)
@@ -160,7 +154,7 @@ static RTLIL::Const logic_wrapper(RTLIL::State(*logic_func)(RTLIL::State, RTLIL:
 		RTLIL::Const arg1, RTLIL::Const arg2, bool signed1, bool signed2, int result_len = -1)
 {
 	if (result_len < 0)
-		result_len = std::max(arg1.bits.size(), arg2.bits.size());
+		result_len = max(arg1.bits.size(), arg2.bits.size());
 
 	extend_u0(arg1, result_len, signed1);
 	extend_u0(arg2, result_len, signed2);
@@ -281,10 +275,15 @@ RTLIL::Const RTLIL::const_logic_or(const RTLIL::Const &arg1, const RTLIL::Const
 	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();
@@ -296,9 +295,9 @@ static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Co
 	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 >= 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()];
 	}
@@ -310,61 +309,36 @@ RTLIL::Const RTLIL::const_shl(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 {
 	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, std::max(result_len, SIZE(arg1)), signed1);
-	return const_shift_worker(arg1_ext, arg2, false, +1, result_len);
+	extend_u0(arg1_ext, max(result_len, GetSize(arg1)), signed1);
+	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 >= 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)
@@ -395,7 +369,7 @@ RTLIL::Const RTLIL::const_eq(const RTLIL::Const &arg1, const RTLIL::Const &arg2,
 	RTLIL::Const arg2_ext = arg2;
 	RTLIL::Const result(RTLIL::State::S0, result_len);
 
-	int width = std::max(arg1_ext.bits.size(), arg2_ext.bits.size());
+	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
 	extend_u0(arg1_ext, width, signed1 && signed2);
 	extend_u0(arg2_ext, width, signed1 && signed2);
 
@@ -429,7 +403,7 @@ RTLIL::Const RTLIL::const_eqx(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 	RTLIL::Const arg2_ext = arg2;
 	RTLIL::Const result(RTLIL::State::S0, result_len);
 
-	int width = std::max(arg1_ext.bits.size(), arg2_ext.bits.size());
+	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
 	extend_u0(arg1_ext, width, signed1 && signed2);
 	extend_u0(arg2_ext, width, signed1 && signed2);
 
@@ -478,23 +452,24 @@ RTLIL::Const RTLIL::const_add(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) + const2big(arg2, signed2, undef_bit_pos);
-	return big2const(y, result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
+	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
 }
 
 RTLIL::Const RTLIL::const_sub(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) - const2big(arg2, signed2, undef_bit_pos);
-	return big2const(y, result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
+	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
 }
 
 RTLIL::Const RTLIL::const_mul(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) * const2big(arg2, signed2, undef_bit_pos);
-	return big2const(y, result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), std::min(undef_bit_pos, 0));
+	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;
@@ -505,9 +480,10 @@ RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 	bool result_neg = (a.getSign() == BigInteger::negative) != (b.getSign() == BigInteger::negative);
 	a = a.getSign() == BigInteger::negative ? -a : a;
 	b = b.getSign() == BigInteger::negative ? -b : b;
-	return big2const(result_neg ? -(a / b) : (a / b), result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), std::min(undef_bit_pos, 0));
+	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;
@@ -518,7 +494,52 @@ RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 	bool result_neg = a.getSign() == BigInteger::negative;
 	a = a.getSign() == BigInteger::negative ? -a : a;
 	b = b.getSign() == BigInteger::negative ? -b : b;
-	return big2const(result_neg ? -(a % b) : (a % b), result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), std::min(undef_bit_pos, 0));
+	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)
@@ -569,7 +590,7 @@ RTLIL::Const RTLIL::const_pow(const RTLIL::Const &arg1, const RTLIL::Const &arg2
 			y *= -1;
 	}
 
-	return big2const(y, result_len >= 0 ? result_len : std::max(arg1.bits.size(), arg2.bits.size()), std::min(undef_bit_pos, 0));
+	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
 }
 
 RTLIL::Const RTLIL::const_pos(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
@@ -580,14 +601,6 @@ RTLIL::Const RTLIL::const_pos(const RTLIL::Const &arg1, const RTLIL::Const&, boo
 	return arg1_ext;
 }
 
-RTLIL::Const RTLIL::const_bu0(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
-{
-	RTLIL::Const arg1_ext = arg1;
-	extend_u0(arg1_ext, result_len, signed1);
-
-	return arg1_ext;
-}
-
 RTLIL::Const RTLIL::const_neg(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;