From 0d79158b3bcefd51b92bd70cde69d3a80dcb77b8 Mon Sep 17 00:00:00 2001
From: Helmut Eller <eller.helmut@gmail.com>
Date: Mon, 17 Nov 2025 20:57:18 +0100
Subject: [PATCH] * mps/code/poolamc.c (AMCBufInit): Accept optional
 MPS_KEY_GEN arg.

---
 mps/code/poolamc.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/mps/code/poolamc.c b/mps/code/poolamc.c
index b712ce52370..d1e6960fca2 100644
--- a/mps/code/poolamc.c
+++ b/mps/code/poolamc.c
@@ -519,8 +519,13 @@ static Res AMCBufInit(Buffer buffer, Pool pool, Bool isMutator, ArgList args)
   amcbuf = CouldBeA(amcBuf, buffer);
 
   if (BufferIsMutator(buffer)) {
-    /* Set up the buffer to be allocating in the nursery. */
-    amcbuf->gen = amc->nursery;
+    if (ArgPick(&arg, args, MPS_KEY_GEN)) {
+      unsigned gen = arg.val.u;
+      amcbuf->gen = amc->gen[gen];
+    } else {
+      /* Set up the buffer to be allocating in the nursery. */
+      amcbuf->gen = amc->nursery;
+    }
   } else {
     /* No gen yet -- see <design/poolamc#.gen.forward>. */
     amcbuf->gen = NULL;