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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 17:43:51 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-21 17:43:51 +0000
commitbe58c81aff4cd4c0ccf43dbd7998da4a6a08c03b (patch)
tree779c248fb61c83f65d1f0dc867f2053d76b4e03a /lib/aarch32/arm32_aeabi_divmod.c
parentInitial commit. (diff)
downloadarm-trusted-firmware-be58c81aff4cd4c0ccf43dbd7998da4a6a08c03b.tar.xz
arm-trusted-firmware-be58c81aff4cd4c0ccf43dbd7998da4a6a08c03b.zip
Adding upstream version 2.10.0+dfsg.upstream/2.10.0+dfsgupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'lib/aarch32/arm32_aeabi_divmod.c')
-rw-r--r--lib/aarch32/arm32_aeabi_divmod.c156
1 files changed, 156 insertions, 0 deletions
diff --git a/lib/aarch32/arm32_aeabi_divmod.c b/lib/aarch32/arm32_aeabi_divmod.c
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+/*
+ * Copyright (c) 2017-2019, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+/*
+ * Form ABI specifications:
+ * int __aeabi_idiv(int numerator, int denominator);
+ * unsigned __aeabi_uidiv(unsigned numerator, unsigned denominator);
+ *
+ * typedef struct { int quot; int rem; } idiv_return;
+ * typedef struct { unsigned quot; unsigned rem; } uidiv_return;
+ *
+ * __value_in_regs idiv_return __aeabi_idivmod(int numerator,
+ * int *denominator);
+ * __value_in_regs uidiv_return __aeabi_uidivmod(unsigned *numerator,
+ * unsigned denominator);
+ */
+
+/* struct qr - stores quotient/remainder to handle divmod EABI interfaces. */
+struct qr {
+ unsigned int q; /* computed quotient */
+ unsigned int r; /* computed remainder */
+ unsigned int q_n; /* specifies if quotient shall be negative */
+ unsigned int r_n; /* specifies if remainder shall be negative */
+};
+
+static void uint_div_qr(unsigned int numerator, unsigned int denominator,
+ struct qr *qr);
+
+/* returns in R0 and R1 by tail calling an asm function */
+unsigned int __aeabi_uidivmod(unsigned int numerator, unsigned int denominator);
+
+unsigned int __aeabi_uidiv(unsigned int numerator, unsigned int denominator);
+
+/* returns in R0 and R1 by tail calling an asm function */
+signed int __aeabi_idivmod(signed int numerator, signed int denominator);
+
+signed int __aeabi_idiv(signed int numerator, signed int denominator);
+
+/*
+ * __ste_idivmod_ret_t __aeabi_idivmod(signed numerator, signed denominator)
+ * Numerator and Denominator are received in R0 and R1.
+ * Where __ste_idivmod_ret_t is returned in R0 and R1.
+ *
+ * __ste_uidivmod_ret_t __aeabi_uidivmod(unsigned numerator,
+ * unsigned denominator)
+ * Numerator and Denominator are received in R0 and R1.
+ * Where __ste_uidivmod_ret_t is returned in R0 and R1.
+ */
+#ifdef __GNUC__
+signed int ret_idivmod_values(signed int quotient, signed int remainder);
+unsigned int ret_uidivmod_values(unsigned int quotient, unsigned int remainder);
+#else
+#error "Compiler not supported"
+#endif
+
+static void division_qr(unsigned int n, unsigned int p, struct qr *qr)
+{
+ unsigned int i = 1, q = 0;
+
+ if (p == 0) {
+ qr->r = 0xFFFFFFFF; /* division by 0 */
+ return;
+ }
+
+ while ((p >> 31) == 0) {
+ i = i << 1; /* count the max division steps */
+ p = p << 1; /* increase p until it has maximum size*/
+ }
+
+ while (i > 0) {
+ q = q << 1; /* write bit in q at index (size-1) */
+ if (n >= p) {
+ n -= p;
+ q++;
+ }
+ p = p >> 1; /* decrease p */
+ i = i >> 1; /* decrease remaining size in q */
+ }
+ qr->r = n;
+ qr->q = q;
+}
+
+static void uint_div_qr(unsigned int numerator, unsigned int denominator,
+ struct qr *qr)
+{
+ division_qr(numerator, denominator, qr);
+
+ /* negate quotient and/or remainder according to requester */
+ if (qr->q_n)
+ qr->q = -qr->q;
+ if (qr->r_n)
+ qr->r = -qr->r;
+}
+
+unsigned int __aeabi_uidiv(unsigned int numerator, unsigned int denominator)
+{
+ struct qr qr = { .q_n = 0, .r_n = 0 };
+
+ uint_div_qr(numerator, denominator, &qr);
+
+ return qr.q;
+}
+
+unsigned int __aeabi_uidivmod(unsigned int numerator, unsigned int denominator)
+{
+ struct qr qr = { .q_n = 0, .r_n = 0 };
+
+ uint_div_qr(numerator, denominator, &qr);
+
+ return ret_uidivmod_values(qr.q, qr.r);
+}
+
+signed int __aeabi_idiv(signed int numerator, signed int denominator)
+{
+ struct qr qr = { .q_n = 0, .r_n = 0 };
+
+ if (((numerator < 0) && (denominator > 0)) ||
+ ((numerator > 0) && (denominator < 0)))
+ qr.q_n = 1; /* quotient shall be negate */
+
+ if (numerator < 0) {
+ numerator = -numerator;
+ qr.r_n = 1; /* remainder shall be negate */
+ }
+
+ if (denominator < 0)
+ denominator = -denominator;
+
+ uint_div_qr(numerator, denominator, &qr);
+
+ return qr.q;
+}
+
+signed int __aeabi_idivmod(signed int numerator, signed int denominator)
+{
+ struct qr qr = { .q_n = 0, .r_n = 0 };
+
+ if (((numerator < 0) && (denominator > 0)) ||
+ ((numerator > 0) && (denominator < 0)))
+ qr.q_n = 1; /* quotient shall be negate */
+
+ if (numerator < 0) {
+ numerator = -numerator;
+ qr.r_n = 1; /* remainder shall be negate */
+ }
+
+ if (denominator < 0)
+ denominator = -denominator;
+
+ uint_div_qr(numerator, denominator, &qr);
+
+ return ret_idivmod_values(qr.q, qr.r);
+}