From a761d0e4efd97e140e6a2a879cd3b34993059251 Mon Sep 17 00:00:00 2001 From: "Kartik K. Agaram" Date: Sun, 25 Apr 2021 16:02:30 -0700 Subject: [PATCH] a troubleshooting note --- shell/README.md | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/shell/README.md b/shell/README.md index 6a6dd3e0..6c83c08f 100644 --- a/shell/README.md +++ b/shell/README.md @@ -65,3 +65,14 @@ $ qemu-system-i386 -m 2G -enable-kvm -hda code.img -hdb data.img * Don't press keys too quickly (such as by holding down a key). The Mu computer will crash (and often Qemu will segfault). + +* Mu currently assumes access to 2GB of RAM. To change that, modify the + definition of `Heap` in 120allocate.subx, and then modify the `-m 2G` + argument in the Qemu commands above. Mu currently has no virtual + memory. If your Heap is too large for RAM, allocating past the end of RAM + will succeed. However, accessing addresses not backed by RAM will fail with + this error: + + ``` + lookup: failed + ```