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Assembler Mystery Cache

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Mensi trapeni na dlouhe zimni vecery


Assembler

V nasem pripade konkretne kod pro procesory Microchip rady PIC16x, jde o procesory typu RISC s 35ti zakladnimi instrukcemi.

Seznam vsech instrukci a jejich popis je zde nebo mozno vyuzit strycka Google.

 

Zapis instrukce jazyka ASSEMBLER se sklada ze dvou casti a to z vlastniho kodoveho slova instrukce a tzv. operandu.

Nasledujici priklad instrukce provede zapis dat z registru W  (pracovni registr) do registru se symbolickym názvem MojeBunka.

 

MOVWF MojeBunka

a opacne:

MOVF MojeBunka, 0

kde prave 0 oznacuje umisteni do W registru.

 

Potrebne konstanty pro vylusteni:

Const_D EQU b'00001100'
Const_M EQU b'00001000'
Const_R_H EQU b'00000111'
Const_R_L EQU b'11011111'

 

Samotny kod pro ziskani souradnic:

MOVLW Const_D
MOVWF Mem_W
RLF Mem_W,1
RLF Mem_W,0
ADDLW 0x01
MOVWF Gps_N_Deg

MOVLW Const_R_L
XORLW 0xFF
MOVWF Mem_W
SWAPF Mem_W,1
XORWF Mem_W,0
MOVWF Gps_N_Dec

MOVLW Const_M
MOVWF Mem_W
RLF Mem_W,1
SWAPF Mem_W,0
MOVWF Gps_N_Min_H

MOVLW Const_R_L
SUBLW 0x58
BTFSC STATUS,C
ADDLW 0xC0
MOVWF Gps_N_Min_L

MOVF Gps_N_Deg,0
XORWF Gps_N_Dec,0
MOVWF Mem_W
BTFSC Mem_W,1
BCF Mem_W,1
MOVF Mem_W,0
MOVWF Gps_E_Deg

MOVLW Const_M
MOVWF Mem_W
RLF Mem_W,0
MOVWF Gps_E_Dec

MOVLW Const_R_H
MOVWF Mem_W
SWAPF Mem_W,1
RRF Mem_W,1
BTFSS STATUS,C
CLRW
MOVWF Gps_E_Min_H

MOVLW Const_R_L
MOVWF Mem_W
BCF Mem_W,4
MOVF Mem_W,0
MOVWF Gps_E_Min_L

 

upozorneni:

Minuty v souradnicich jsou 16ti bitove.

Na vychozich souradnicich kes nehledejte, naleznete zde jen obchod s elektro soucastkami :)

Pro prvni tri nalezce jsou v kesi urcene mikroprocesory PIC :-)

Additional Hints (Decrypt)

10 zrgeh frirear bq gensbfgnavpr

Decryption Key

A|B|C|D|E|F|G|H|I|J|K|L|M
-------------------------
N|O|P|Q|R|S|T|U|V|W|X|Y|Z

(letter above equals below, and vice versa)