1 files changed, 59 insertions, 0 deletions
diff --git a/lib/builtins/arm/fp_mode.c b/lib/builtins/arm/fp_mode.c
new file mode 100644
index 000000000..300b71935
--- /dev/null
+++ b/lib/builtins/arm/fp_mode.c
@@ -0,0 +1,59 @@
+//===----- lib/arm/fp_mode.c - Floaing-point mode utilities -------*- C -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <stdint.h>
+
+#include "../fp_mode.h"
+
+#define ARM_TONEAREST  0x0
+#define ARM_UPWARD     0x1
+#define ARM_DOWNWARD   0x2
+#define ARM_TOWARDZERO 0x3
+#define ARM_RMODE_MASK (ARM_TONEAREST | ARM_UPWARD | \
+                        ARM_DOWNWARD | ARM_TOWARDZERO)
+#define ARM_RMODE_SHIFT 22
+
+#define ARM_INEXACT     0x1000
+
+#ifndef __ARM_FP
+// For soft float targets, allow changing rounding mode by overriding the weak
+// __arm_fe_default_rmode symbol.
+FE_ROUND_MODE __attribute__((weak)) __arm_fe_default_rmode = FE_TONEAREST;
+#endif
+
+FE_ROUND_MODE __fe_getround() {
+#ifdef __ARM_FP
+  uint32_t fpscr;
+  __asm__ __volatile__("vmrs  %0, fpscr" : "=r" (fpscr));
+  fpscr = fpscr >> ARM_RMODE_SHIFT & ARM_RMODE_MASK;
+  switch (fpscr) {
+    case ARM_UPWARD:
+      return FE_UPWARD;
+    case ARM_DOWNWARD:
+      return FE_DOWNWARD;
+    case ARM_TOWARDZERO:
+      return FE_TOWARDZERO;
+    case ARM_TONEAREST:
+    default:
+      return FE_TONEAREST;
+  }
+#else
+  return __arm_fe_default_rmode;
+#endif
+}
+
+int __fe_raise_inexact() {
+#ifdef __ARM_FP
+  uint32_t fpscr;
+  __asm__ __volatile__("vmrs  %0, fpscr" : "=r" (fpscr));
+  __asm__ __volatile__("vmsr  fpscr, %0" : : "ri" (fpscr | ARM_INEXACT));
+  return 0;
+#else
+  return 0;
+#endif
+}