[PULL 11/54] libdecnumber: introduce decNumberFrom[U]Int128

[David Gibson]

From: Luis Pires <luis.pires@eldorado.org.br>

This will be used to implement PowerPC's dcffixqq.

Signed-off-by: Luis Pires <luis.pires@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20211029192417.400707-2-luis.pires@eldorado.org.br>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 include/libdecnumber/decNumber.h |  2 ++
 libdecnumber/decNumber.c         | 36 ++++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+)

diff --git a/include/libdecnumber/decNumber.h b/include/libdecnumber/decNumber.h
index aa115fed07..0cf69c7db2 100644
--- a/include/libdecnumber/decNumber.h
+++ b/include/libdecnumber/decNumber.h
@@ -116,6 +116,8 @@
   decNumber * decNumberFromUInt32(decNumber *, uint32_t);
   decNumber *decNumberFromInt64(decNumber *, int64_t);
   decNumber *decNumberFromUInt64(decNumber *, uint64_t);
+  decNumber *decNumberFromInt128(decNumber *, uint64_t, int64_t);
+  decNumber *decNumberFromUInt128(decNumber *, uint64_t, uint64_t);
   decNumber * decNumberFromString(decNumber *, const char *, decContext *);
   char     * decNumberToString(const decNumber *, char *);
   char     * decNumberToEngString(const decNumber *, char *);
diff --git a/libdecnumber/decNumber.c b/libdecnumber/decNumber.c
index 1ffe458ad8..d7716ce175 100644
--- a/libdecnumber/decNumber.c
+++ b/libdecnumber/decNumber.c
@@ -167,6 +167,7 @@
 /* ------------------------------------------------------------------ */
 
 #include "qemu/osdep.h"
+#include "qemu/host-utils.h"
 #include "libdecnumber/dconfig.h"
 #include "libdecnumber/decNumber.h"
 #include "libdecnumber/decNumberLocal.h"
@@ -462,6 +463,41 @@ decNumber *decNumberFromUInt64(decNumber *dn, uint64_t uin)
     return dn;
 } /* decNumberFromUInt64 */
 
+decNumber *decNumberFromInt128(decNumber *dn, uint64_t lo, int64_t hi)
+{
+    uint64_t unsig_hi = hi;
+    if (hi < 0) {
+        if (lo == 0) {
+            unsig_hi = -unsig_hi;
+        } else {
+            unsig_hi = ~unsig_hi;
+            lo = -lo;
+        }
+    }
+
+    decNumberFromUInt128(dn, lo, unsig_hi);
+    if (hi < 0) {
+        dn->bits = DECNEG;        /* sign needed */
+    }
+    return dn;
+} /* decNumberFromInt128 */
+
+decNumber *decNumberFromUInt128(decNumber *dn, uint64_t lo, uint64_t hi)
+{
+    uint64_t rem;
+    Unit *up;                             /* work pointer */
+    decNumberZero(dn);                    /* clean */
+    if (lo == 0 && hi == 0) {
+        return dn;                /* [or decGetDigits bad call] */
+    }
+    for (up = dn->lsu; hi > 0 || lo > 0; up++) {
+        rem = divu128(&lo, &hi, DECDPUNMAX + 1);
+        *up = (Unit)rem;
+    }
+    dn->digits = decGetDigits(dn->lsu, up - dn->lsu);
+    return dn;
+} /* decNumberFromUInt128 */
+
 /* ------------------------------------------------------------------ */
 /* to-int64 -- conversion to int64                                    */
 /*                                                                    */
-- 
2.33.1