Add qemu 2.4.0

[kvmfornfv.git] / qemu / roms / SLOF / slof / fs / stack.fs

diff --git a/qemu/roms/SLOF/slof/fs/stack.fs b/qemu/roms/SLOF/slof/fs/stack.fs
new file mode 100644 (file)
index 0000000..0f7e097
--- /dev/null
+++ b/qemu/roms/SLOF/slof/fs/stack.fs
@@ -0,0 +1,57 @@
+\ *****************************************************************************
+\ * Copyright (c) 2004, 2008 IBM Corporation
+\ * All rights reserved.
+\ * This program and the accompanying materials
+\ * are made available under the terms of the BSD License
+\ * which accompanies this distribution, and is available at
+\ * http://www.opensource.org/licenses/bsd-license.php
+\ *
+\ * Contributors:
+\ *     IBM Corporation - initial implementation
+\ ****************************************************************************/
+
+
+\ Example:
+\
+\ To get a 30 element stack, go:
+\
+\ 0 > 30 new-stack my-stack
+\ 0 > my-stack
+\ 0 > 20 push 30 push
+\ 0 > pop pop .s
+
+0 value current-stack
+
+: new-stack ( cells <>name -- )
+   create >r here    ( here R: cells )
+   dup r@ 2 + cells  ( here here bytes R: cells )
+   dup allot erase   ( here R: cells)
+   cell+ r>          ( here+1cell cells )
+   swap !            ( )
+   DOES> to current-stack
+;
+
+: reset-stack ( -- )
+   0 current-stack !
+;
+
+: stack-depth ( -- depth )
+   current-stack @
+;
+
+: push ( value -- )
+   current-stack @
+   current-stack cell+ @ over <= ABORT" Stack overflow"
+   cells
+   1 current-stack +!
+   current-stack 2 cells + + !
+;
+
+: pop ( -- value )
+   current-stack @ 0= ABORT" Stack underflow"
+   current-stack @ cells
+   current-stack + cell+ @
+   -1 current-stack +!
+;
+
+