[PATCH 2/5] lib/eal: add portable version of __builtin_add_overflow
Andre Muezerie
andremue at linux.microsoft.com
Thu Jan 2 23:32:45 CET 2025
__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.
This patch introduces __rte_add_overflow_u8, __rte_add_overflow_u16
and __rte_add_overflow_u32.
Signed-off-by: Andre Muezerie <andremue at linux.microsoft.com>
---
lib/eal/include/meson.build | 1 +
lib/eal/include/rte_math.h | 42 +++++++++++++++++++++++++++++++++++++
2 files changed, 43 insertions(+)
create mode 100644 lib/eal/include/rte_math.h
diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
index d903577caa..041a4105b5 100644
--- a/lib/eal/include/meson.build
+++ b/lib/eal/include/meson.build
@@ -31,6 +31,7 @@ headers += files(
'rte_lcore_var.h',
'rte_lock_annotations.h',
'rte_malloc.h',
+ 'rte_math.h',
'rte_mcslock.h',
'rte_memory.h',
'rte_memzone.h',
diff --git a/lib/eal/include/rte_math.h b/lib/eal/include/rte_math.h
new file mode 100644
index 0000000000..df2f3d4d34
--- /dev/null
+++ b/lib/eal/include/rte_math.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2025 Microsoft Corporation
+ */
+
+#ifndef _RTE_MATH_H_
+#define _RTE_MATH_H_
+
+/**
+ * @file
+ *
+ * Math function definitions for DPDK.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Functions that allow performing simple arithmetic operations together with
+ * checking whether the operations overflowed.
+ * Example of usage:
+ * uint8_t overflow;
+ * uint16_t a, b, result;
+ * a = 1;
+ * b = 2;
+ * overflow = __rte_add_overflow_u16(a, b, &result);
+ */
+#ifdef RTE_TOOLCHAIN_MSVC
+#define __rte_add_overflow_u8(a, b, res) _addcarry_u8(0, a, b, res)
+#define __rte_add_overflow_u16(a, b, res) _addcarry_u16(0, a, b, res)
+#define __rte_add_overflow_u32(a, b, res) _addcarry_u32(0, a, b, res)
+#else
+#define __rte_add_overflow_u8(a, b, res) __builtin_add_overflow(a, b, res)
+#define __rte_add_overflow_u16(a, b, res) __builtin_add_overflow(a, b, res)
+#define __rte_add_overflow_u32(a, b, res) __builtin_add_overflow(a, b, res)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
--
2.47.0.vfs.0.3
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