[PATCH 2/8] compiler-rt: Add __multi3

[Vladimir Serbinenko]

It's necessary for clang sparc64 support
---
 grub-core/kern/compiler-rt.c | 58 ++++++++++++++++++++++++++++++++++++
 include/grub/compiler-rt.h   |  7 +++++
 2 files changed, 65 insertions(+)

diff --git a/grub-core/kern/compiler-rt.c b/grub-core/kern/compiler-rt.c
index eda689a0c..2902ed03d 100644
--- a/grub-core/kern/compiler-rt.c
+++ b/grub-core/kern/compiler-rt.c
@@ -452,3 +452,61 @@ __clzdi2 (grub_uint64_t val)
     }
 }
 #endif
+
+#if defined(__sparc__) && defined(__clang__)
+/* Copied from multi3.c which is under MIT license.  */
+typedef          long long di_int;
+typedef unsigned long long du_int;
+
+typedef union
+{
+    grub_clang_ti_int all;
+    struct
+    {
+#ifndef GRUB_CPU_WORDS_BIGENDIAN
+        du_int low;
+        di_int high;
+#else
+        di_int high;
+        du_int low;
+#endif /* _YUGA_LITTLE_ENDIAN */
+    }s;
+} twords;
+
+static
+grub_clang_ti_int
+__mulddi3(du_int a, du_int b)
+{
+    twords r;
+    const int bits_in_dword_2 = (int)(sizeof(di_int) * 8) / 2;
+    const du_int lower_mask = (du_int)~0 >> bits_in_dword_2;
+    r.s.low = (a & lower_mask) * (b & lower_mask);
+    du_int t = r.s.low >> bits_in_dword_2;
+    r.s.low &= lower_mask;
+    t += (a >> bits_in_dword_2) * (b & lower_mask);
+    r.s.low += (t & lower_mask) << bits_in_dword_2;
+    r.s.high = t >> bits_in_dword_2;
+    t = r.s.low >> bits_in_dword_2;
+    r.s.low &= lower_mask;
+    t += (b >> bits_in_dword_2) * (a & lower_mask);
+    r.s.low += (t & lower_mask) << bits_in_dword_2;
+    r.s.high += t >> bits_in_dword_2;
+    r.s.high += (a >> bits_in_dword_2) * (b >> bits_in_dword_2);
+    return r.all;
+}
+
+/* Returns: a * b */
+
+grub_clang_ti_int
+__multi3(grub_clang_ti_int a, grub_clang_ti_int b)
+{
+    twords x;
+    x.all = a;
+    twords y;
+    y.all = b;
+    twords r;
+    r.all = __mulddi3(x.s.low, y.s.low);
+    r.s.high += x.s.high * y.s.low + x.s.low * y.s.high;
+    return r.all;
+}
+#endif
diff --git a/include/grub/compiler-rt.h b/include/grub/compiler-rt.h
index 17828b322..3637db47e 100644
--- a/include/grub/compiler-rt.h
+++ b/include/grub/compiler-rt.h
@@ -209,5 +209,12 @@ void EXPORT_FUNC (___chkstk_ms) (void);
 void EXPORT_FUNC (__chkstk_ms) (void);
 #endif
 
+#if defined(__sparc__) && defined(__clang__)
+/* Copied from multi3.c which is under MIT license.  */
+typedef int      grub_clang_ti_int __attribute__ ((mode (TI)));
+
+grub_clang_ti_int EXPORT_FUNC(__multi3) (grub_clang_ti_int a, 
grub_clang_ti_int b);
+#endif
+
 #endif
 
-- 
2.39.2