diff options
Diffstat (limited to 'qemu/roms/SLOF/slof/fs/stack.fs')
| -rw-r--r-- | qemu/roms/SLOF/slof/fs/stack.fs | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/qemu/roms/SLOF/slof/fs/stack.fs b/qemu/roms/SLOF/slof/fs/stack.fs new file mode 100644 index 000000000..0f7e097bf --- /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 +! +; + + |