From d5510a546f52ccb5752b92d534589fd178793b09 Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@twiddle.net>
Date: Tue, 27 Feb 2018 11:06:30 -0500
Subject: [PATCH] int128: Add int128_make128

Allows Int128 to be used more generally, rather than having to
begin with 64-bit inputs and accumulate.

Backports commit 1edaeee0955fba7d834b7c8f4e372e7eae030745 from qemu
---
 qemu/include/qemu/int128.h | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/qemu/include/qemu/int128.h b/qemu/include/qemu/int128.h
index d3907b5b..70ffa9b2 100644
--- a/qemu/include/qemu/int128.h
+++ b/qemu/include/qemu/int128.h
@@ -12,6 +12,11 @@ static inline Int128 int128_make64(uint64_t a)
     return a;
 }
 
+static inline Int128 int128_make128(uint64_t lo, uint64_t hi)
+{
+    return (__uint128_t)hi << 64 | lo;
+}
+
 static inline uint64_t int128_get64(Int128 a)
 {
     uint64_t r = a;
@@ -149,6 +154,14 @@ static inline Int128 int128_make64(uint64_t a)
     return i128;
 }
 
+static inline Int128 int128_make128(uint64_t lo, uint64_t hi)
+{
+    Int128 res;
+    res.lo = lo;
+    res.hi = hi;
+    return res;
+}
+
 static inline uint64_t int128_get64(Int128 a)
 {
     //assert(!a.hi);
@@ -201,11 +214,9 @@ static inline Int128 int128_rshift(Int128 a, int n)
     }
     h = a.hi >> (n & 63);
     if (n >= 64) {
-        Int128 i128 = { h, h >> 63 };
-        return i128;
+        return int128_make128(h, h >> 63);
     } else {
-        Int128 i128 = { (a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h };
-        return i128;
+        return int128_make128((a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h);
     }
 }
 
@@ -219,21 +230,18 @@ static inline Int128 int128_add(Int128 a, Int128 b)
      *
      * So the carry is lo < a.lo.
      */
-    Int128 i128 = { lo, (uint64_t)a.hi + b.hi + (lo < a.lo) };
-    return i128;
+    return int128_make128(lo, (uint64_t)a.hi + b.hi + (lo < a.lo));
 }
 
 static inline Int128 int128_neg(Int128 a)
 {
     uint64_t lo = 0-a.lo;
-    Int128 i128 = { lo, ~(uint64_t)a.hi + !lo };
-    return i128;
+    return int128_make128(lo, ~(uint64_t)a.hi + !lo);
 }
 
 static inline Int128 int128_sub(Int128 a, Int128 b)
 {
-    Int128 i128 = { a.lo - b.lo, (uint64_t)a.hi - b.hi - (a.lo < b.lo) };
-    return i128;
+    return int128_make128(a.lo - b.lo, (uint64_t)a.hi - b.hi - (a.lo < b.lo));
 }
 
 static inline bool int128_nonneg(Int128 a)