ARTEAM EZINE ISSUE IV
any superclasses). After this are pairs of 16-bit integers, with the first integer in each pair containing a selector defined in the class, and the second integer in each pair containing the byte offset to the method for that selector (the offset is from the start of the compiled class data, i.e., from the number-of-selectors word above). The selectors are sorted in ascending order. When looking up a method at runtime, a binary search is performed (in contrast to the hash table mechanism used by other Smalltalks). In general, the binary search is just as fast as a hash table (and faster for classes with large numbers of methods), and it saves space because there are no unused slots. After the selector/offset table come the instructions of the methods, one after the other. The methods are completely linear; in other words, no "literal table" is needed. Therefore compiled methods need no extra structure and need not be scanned by the garbage collector at runtime.
4.3.4
PALM OS OPERATING SYSTEM
In the world of win32 reversing on x86 architectures we have registers like EDX,EAX,ESP etc. Palm have 8 data registers, these are: D0, D1, D2, D3, D4, D5, D6 and D7. We also have 8 address registers: A0, A1, A2, A3, A4, A5, A6 and A7, where A7 (USP/SSP) works as a stack pointer. We are dealing with 68k assembly which has a different instruction set, and the syntax is opposite of windows. Examples for further comprehension: MOV destination, source (Intel) corresponds to MOV source, destination MOV EDX, ECX (Intel) corresponds to MOV ECX, EDX Another thing you should be aware of is that on Palm the code "branches", while on windows it "jumps". The only real difference is the name of the instructions.
4.3.5 OTHER TOOLS PRCExplorer: Using this tool you can open any PRC file and navigate into it. You can see individual resources, graphically display Forms and Alerts, Bitmaps, Fonts, ... This is useful to debug and develop your application as well as analyzing PRCs. Palm Debugger: Our second debugger. Manage all PDB data and Resources on-line from Palm device. Ideal for debugging, analyze and fix problems. Get information about: Device resources: view statistics, software versions, etc. DataBases: view, Sort and Print all data, size, version, and backup and records information. You can Add, Delete, Modify or Search specific data. Applications: analyze structure, size, version, related databases, date info and much more! X-Master: X-Master is an extension manager similar to HackMaster, but it is designed to offer various technical and user-interface improvements. It is fully compatible with HackMaster, all existing Hacks are supported, and
Primer on Reversing PalmOS Applications Extended Edition by, Wast3d_Bytes, Suntzu
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