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