GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/bootloader/u-boot-2020.01/arch/arc/lib/libgcc2.c

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+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 1989-2013 Free Software Foundation, Inc.
+ */
+
+#include "libgcc2.h"
+
+DWtype
+__ashldi3(DWtype u, shift_count_type b)
+{
+	if (b == 0)
+		return u;
+
+	const DWunion uu = {.ll = u};
+	const shift_count_type bm = W_TYPE_SIZE - b;
+	DWunion w;
+
+	if (bm <= 0) {
+		w.s.low = 0;
+		w.s.high = (UWtype)uu.s.low << -bm;
+	} else {
+		const UWtype carries = (UWtype) uu.s.low >> bm;
+
+		w.s.low = (UWtype)uu.s.low << b;
+		w.s.high = ((UWtype)uu.s.high << b) | carries;
+	}
+
+	return w.ll;
+}
+
+DWtype
+__ashrdi3(DWtype u, shift_count_type b)
+{
+	if (b == 0)
+		return u;
+
+	const DWunion uu = {.ll = u};
+	const shift_count_type bm = W_TYPE_SIZE - b;
+	DWunion w;
+
+	if (bm <= 0) {
+		/* w.s.high = 1..1 or 0..0 */
+		w.s.high = uu.s.high >> (W_TYPE_SIZE - 1);
+		w.s.low = uu.s.high >> -bm;
+	} else {
+		const UWtype carries = (UWtype) uu.s.high << bm;
+
+		w.s.high = uu.s.high >> b;
+		w.s.low = ((UWtype)uu.s.low >> b) | carries;
+	}
+
+	return w.ll;
+}
+
+DWtype
+__lshrdi3(DWtype u, shift_count_type b)
+{
+	if (b == 0)
+		return u;
+
+	const DWunion uu = {.ll = u};
+	const shift_count_type bm = W_TYPE_SIZE - b;
+	DWunion w;
+
+	if (bm <= 0) {
+		w.s.high = 0;
+		w.s.low = (UWtype)uu.s.high >> -bm;
+	} else {
+		const UWtype carries = (UWtype)uu.s.high << bm;
+
+		w.s.high = (UWtype)uu.s.high >> b;
+		w.s.low = ((UWtype)uu.s.low >> b) | carries;
+	}
+
+	return w.ll;
+}
+
+unsigned long
+udivmodsi4(unsigned long num, unsigned long den, int modwanted)
+{
+	unsigned long bit = 1;
+	unsigned long res = 0;
+
+	while (den < num && bit && !(den & (1L<<31))) {
+		den <<= 1;
+		bit <<= 1;
+	}
+
+	while (bit) {
+		if (num >= den) {
+			num -= den;
+			res |= bit;
+		}
+		bit >>= 1;
+		den >>= 1;
+	}
+
+	if (modwanted)
+		return num;
+
+	return res;
+}
+
+long
+__divsi3(long a, long b)
+{
+	int neg = 0;
+	long res;
+
+	if (a < 0) {
+		a = -a;
+		neg = !neg;
+	}
+
+	if (b < 0) {
+		b = -b;
+		neg = !neg;
+	}
+
+	res = udivmodsi4(a, b, 0);
+
+	if (neg)
+		res = -res;
+
+	return res;
+}
+
+long
+__modsi3(long a, long b)
+{
+	int neg = 0;
+	long res;
+
+	if (a < 0) {
+		a = -a;
+		neg = 1;
+	}
+
+	if (b < 0)
+		b = -b;
+
+	res = udivmodsi4(a, b, 1);
+
+	if (neg)
+		res = -res;
+
+	return res;
+}
+
+long
+__udivsi3(long a, long b)
+{
+	return udivmodsi4(a, b, 0);
+}
+
+long
+__umodsi3(long a, long b)
+{
+	return udivmodsi4(a, b, 1);
+}
+
+UDWtype
+__udivmoddi4(UDWtype n, UDWtype d, UDWtype *rp)
+{
+	UDWtype q = 0, r = n, y = d;
+	UWtype lz1, lz2, i, k;
+
+	/*
+	 * Implements align divisor shift dividend method. This algorithm
+	 * aligns the divisor under the dividend and then perform number of
+	 * test-subtract iterations which shift the dividend left. Number of
+	 * iterations is k + 1 where k is the number of bit positions the
+	 * divisor must be shifted left  to align it under the dividend.
+	 * quotient bits can be saved in the rightmost positions of the
+	 * dividend as it shifts left on each test-subtract iteration.
+	 */
+
+	if (y <= r) {
+		lz1 = __builtin_clzll(d);
+		lz2 = __builtin_clzll(n);
+
+		k = lz1 - lz2;
+		y = (y << k);
+
+		/*
+		 * Dividend can exceed 2 ^ (width - 1) - 1 but still be less
+		 * than the aligned divisor. Normal iteration can drops the
+		 * high order bit of the dividend. Therefore, first
+		 * test-subtract iteration is a special case, saving its
+		 * quotient bit in a separate location and not shifting
+		 * the dividend.
+		 */
+
+		if (r >= y) {
+			r = r - y;
+			q = (1ULL << k);
+		}
+
+		if (k > 0) {
+			y = y >> 1;
+
+			/*
+			 * k additional iterations where k regular test
+			 * subtract shift dividend iterations are done.
+			 */
+			i = k;
+			do {
+				if (r >= y)
+					r = ((r - y) << 1) + 1;
+				else
+					r = (r << 1);
+				i = i - 1;
+			} while (i != 0);
+
+			/*
+			 * First quotient bit is combined with the quotient
+			 * bits resulting from the k regular iterations.
+			 */
+			q = q + r;
+			r = r >> k;
+			q = q - (r << k);
+		}
+	}
+
+	if (rp)
+		*rp = r;
+
+	return q;
+}
+
+UDWtype
+__udivdi3(UDWtype n, UDWtype d)
+{
+	return __udivmoddi4(n, d, (UDWtype *)0);
+}