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changeset 33:4655b49eaf9f

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Backed out changeset 6c91cd9a2f2d
author Paper <paper@tflc.us>
date Fri, 25 Apr 2025 17:40:42 -0400
parents 0de48dc864ea
children 8b5e0974fd41
files include/vec/vec.h
diffstat 1 files changed, 12 insertions(+), 7 deletions(-) [+]
line wrap: on
line diff
--- a/include/vec/vec.h	Fri Apr 25 17:40:38 2025 -0400
+++ b/include/vec/vec.h	Fri Apr 25 17:40:42 2025 -0400
@@ -239,14 +239,19 @@
 
 inline vec_intmax vec_avg(vec_intmax x, vec_intmax y)
 {
-    vec_intmax x_d_quot   = (x / 2);
-    vec_intmax x_d_rem    = (x % 2);
-    vec_intmax y_d_quot   = (y / 2);
-    vec_intmax y_d_rem    = (y % 2);
-    vec_intmax rem_d_quot = ((x_d_rem + y_d_rem) / 2);
-    vec_intmax rem_d_rem  = ((x_d_rem + y_d_rem) % 2);
+    if ((x < 0) == (y < 0)) { // same sign
+        // this gets the equivalent of:
+        // vec_int32 r = ((vec_int64)x + (vec_int64)y) / 2;
+        vec_intmax r = (x / 2) + (y / 2) + (((x % 2) + (y % 2)) / 2);
+
+        // FIXME emulate AltiVec quirks
 
-    return (x_d_quot + y_d_quot) + (rem_d_quot) + (rem_d_rem == 1);
+        return r;
+    } else {
+        vec_intmax r = (x + y) / 2;
+        // FIXME emulate AltiVec quirks
+        return r;
+    }
 }
 
 inline vec_uintmax vec_uavg(vec_uintmax x, vec_uintmax y)