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Diffstat (limited to '2024/17/machine.lisp')
| -rw-r--r-- | 2024/17/machine.lisp | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/2024/17/machine.lisp b/2024/17/machine.lisp new file mode 100644 index 0000000..31ae24f --- /dev/null +++ b/2024/17/machine.lisp @@ -0,0 +1,47 @@ +(defpackage #:machine + (:use :cl) + (:export :run)) + +(in-package #:machine) + +;;; Interpreter + +(defconstant +op-adv+ 0) +(defconstant +op-bxl+ 1) +(defconstant +op-bst+ 2) +(defconstant +op-jnz+ 3) +(defconstant +op-bxc+ 4) +(defconstant +op-out+ 5) +(defconstant +op-bdv+ 6) +(defconstant +op-cdv+ 7) + +(defun run (program A B C) + (let ((ip 0) + output) + (flet ((fetch-oprand (oprand) + (case oprand + (4 A) (5 B) (6 C) + (otherwise oprand))) + (xdv (oprand) + (floor A (ash 2 (1- oprand))))) + (loop while (< ip (length program)) do + (let* ((opcode (aref program ip)) + (oprand-lit (aref program (1+ ip))) + (oprand (fetch-oprand oprand-lit))) + (ecase opcode + (#.+op-bxl+ + (setq B (logxor B oprand-lit))) + (#.+op-bst+ + (setq B (logand oprand #b111))) + (#.+op-jnz+ + (unless (zerop A) + (setq ip (- oprand-lit 2)))) + (#.+op-bxc+ + (setq B (logxor B C))) + (#.+op-out+ + (push (logand oprand #b111) output)) + (#.+op-adv+ (setq A (xdv oprand))) + (#.+op-bdv+ (setq B (xdv oprand))) + (#.+op-cdv+ (setq C (xdv oprand)))) + (incf ip 2)))) + (nreverse output)))
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