host-utils: Implemented unsigned 256-by-128 division

Based on already existing QEMU implementation, created an unsigned 256
bit by 128 bit division needed to implement the vector divide extended
unsigned instruction from PowerISA3.1

Signed-off-by: Lucas Mateus Castro (alqotel) <lucas.araujo@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220525134954.85056-5-lucas.araujo@eldorado.org.br>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>

2 files changed, 40 insertions, 0 deletions

diff --git a/include/qemu/host-utils.h b/include/qemu/host-utils.h
index f19bd29..9767af7 100644
--- a/include/qemu/host-utils.h
+++ b/include/qemu/host-utils.h
@@ -32,6 +32,7 @@
 
 #include "qemu/compiler.h"
 #include "qemu/bswap.h"
+#include "qemu/int128.h"
 
 #ifdef CONFIG_INT128
 static inline void mulu64(uint64_t *plow, uint64_t *phigh,
@@ -849,4 +850,5 @@ static inline uint64_t udiv_qrnnd(uint64_t *r, uint64_t n1,
 #endif
 }
 
+Int128 divu256(Int128 *plow, Int128 *phigh, Int128 divisor);
 #endif
diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index ef71f56..d2b76ca 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -128,11 +128,21 @@ static inline bool int128_ge(Int128 a, Int128 b)
     return a >= b;
 }
 
+static inline bool int128_uge(Int128 a, Int128 b)
+{
+    return ((__uint128_t)a) >= ((__uint128_t)b);
+}
+
 static inline bool int128_lt(Int128 a, Int128 b)
 {
     return a < b;
 }
 
+static inline bool int128_ult(Int128 a, Int128 b)
+{
+    return (__uint128_t)a < (__uint128_t)b;
+}
+
 static inline bool int128_le(Int128 a, Int128 b)
 {
     return a <= b;
@@ -177,6 +187,15 @@ static inline Int128 bswap128(Int128 a)
 #endif
 }
 
+static inline int clz128(Int128 a)
+{
+    if (a >> 64) {
+        return __builtin_clzll(a >> 64);
+    } else {
+        return (a) ? __builtin_clzll((uint64_t)a) + 64 : 128;
+    }
+}
+
 static inline Int128 int128_divu(Int128 a, Int128 b)
 {
     return (__uint128_t)a / (__uint128_t)b;
@@ -373,11 +392,21 @@ static inline bool int128_ge(Int128 a, Int128 b)
     return a.hi > b.hi || (a.hi == b.hi && a.lo >= b.lo);
 }
 
+static inline bool int128_uge(Int128 a, Int128 b)
+{
+    return (uint64_t)a.hi > (uint64_t)b.hi || (a.hi == b.hi && a.lo >= b.lo);
+}
+
 static inline bool int128_lt(Int128 a, Int128 b)
 {
     return !int128_ge(a, b);
 }
 
+static inline bool int128_ult(Int128 a, Int128 b)
+{
+    return !int128_uge(a, b);
+}
+
 static inline bool int128_le(Int128 a, Int128 b)
 {
     return int128_ge(b, a);
@@ -418,6 +447,15 @@ static inline Int128 bswap128(Int128 a)
     return int128_make128(bswap64(a.hi), bswap64(a.lo));
 }
 
+static inline int clz128(Int128 a)
+{
+    if (a.hi) {
+        return __builtin_clzll(a.hi);
+    } else {
+        return (a.lo) ? __builtin_clzll(a.lo) + 64 : 128;
+    }
+}
+
 Int128 int128_divu(Int128, Int128);
 Int128 int128_remu(Int128, Int128);
 Int128 int128_divs(Int128, Int128);