No comments:. Newer Post Older Post Home. Subscribe to: Post Comments Atom. Search This Blog. Popular Posts. CSAssembly language Quiz 2 from lecture solved with reference CS Assignment 1 Solution Spring Adobe Premiere CC V But please, please send us bug reports, fixes, helpful information, and anything else you can get your hands on and thanks to the many people who've done this already! You all know who you are , and we'll improve it out of all recognition.
FreeBasic for Windows x64 bit 1. PyCharm R for Windows 4. PyCharm Community Edition Free Pascal 3. This is the project webpage for the Netwide Assembler NASM , an asssembler for the x86 CPU architecture portable to nearly every modern platform, and with code generation for many platforms old and new. As of version 2. The details of the license are available in the documentation.
Stable 2. This requirement is very restrictive to assembler programmers, and causes compilers a big headache. GoAsm's solution to this problem is to insert special coding before and after each API call when INVOKE is used to ensure that the stack is always properly aligned at the time of the call. This liberates the assembler programmer, and means that Bringing together all those considerations and also those set out above, it is perfectly possible to use the same source code to create executables for both bit and bit platforms.
A similar problem arises when interrogating the system and receiving information into data. However assembling and running the same code in a bit system would overwrite the next dword in memory as well a qword is sent not a dword. The optimisations and refinements are listed here to help you when you look at the code produced by GoAsm in the debugger.
Contents Introduction to bit programming: How easy is bit programming? Differences between bit and bit executablestop Although bit and bit executables are based on the same PE Portable Executable format, in fact there are a number of major differences. The extent of those differences means that bit code will only run on Win64 using the Windows on Windows WOW64 subsystem. This works by intercepting API calls from the executable and converting the parameters to suit Win The significance of the above is that the programmer has to choose between:- Making one version of the application Win This will work on both platforms.
Making two versions of the application one for Win32 and one for Win The 'magic number' at the beginning of the optional header is 20Bh instead of 10Bh. The import address table where the loader overwrites the addresses of external calls such as the addresses of APIs in system Dlls is enlarged to bits, as is the import look-up table. This is because the address of external calls could be anywhere in memory. The default base address in Win64 is h as in Win32 files. You can view the internals of the PE file using Wayne J.
Radburn's PEview. Instead this must be done by the caller to the API. The caller must also ensure that there is space on the stack for the API to store the parameters which are passed in registers. In practice this is achieved by reducing the stack pointer by 32 bytes just before the call. This means that your window procedures will pick up the parameters in a different way under Win Also the window procedures no longer have to restore the stack to equilibrium.
All functions using a stack frame including window procedures need to follow certain rules if they wish to make use of exception handling. The tools need also to add exception frame records to the executable. This will also be handled automatically by the 'Go' tools. Note this is not yet available Register volatility.
These are called the 'non-volatile' registers. The 'volatile' registers are those which may be changed by APIs, and which you do not need to save and restore in your window procedures and other callback procedures. You might not have expected this, but in bit assembly for the AMD64, pointers to code and data whose addresses are within the executable are still only bits.
Pointers to external addresses, such as functions in Dlls, are bit wide so that the function can be anywhere in memory see call address sizes. In Win64 the data size of all handles and pointers are now bits instead of bits. See Changes to Windows data types for more. In Win64 there are stricter requirements for the alignment of the stack, data, and for structures see alignment of structures and structure members. The Windows APIs have been modified to work in bits.
There are, however, a small number of new APIs to handle the extra requirements of bit operation. See Writing Unicode programs. Differences between x86 and x64 processorstop The main differences are the expanded register range, some changes to instructions, and the use of RIP-relative addressing. The notes below refer to the AMD64 in bit mode. In this mode the AMD64 can also run bit executables naturally. Registerstop The AMD64 adds several new registers to those available in the 86 series of processors, and also adds new ways to address the existing registers.
You can still access the lowest word of these registers ie. However, the opcodes for this have been altered in the AMD64 processor. They now clash with the opcodes required to address the byte versions of the extended registers R8 to R There are eight new bit registers the 'extended registers' named R8 to R The low dword of these registers ie. The low word of these registers ie.
The first byte of these registers ie. As in the 86 processor they are also used as floating point registers ST0 to ST7 for the x87 floating point instructions. The instruction pointer is now in the bit RIP register. Instructionstop There are some instructions which are not available in the AMD The opcodes are now used for other purposes.
Apart from the above, the only new instruction of any note usable by programmers is MOVSXD which can move bits of data from a register or from memory into a bit register, sign extending bit 31 into all higher bits. There are also a handful of new system instructions. So it does not really matter which you use. There is no single instruction capable of taking a bit immediate value and PUSHing that onto the stack.
The problem here is that the actual immediate value of any particular offset is unknown until link-time, and at assemble-time it is impossible for the assembler to know whether the offset is above 7FFFFFFFh and so would be affected by the sign extension.
It's not clear whether these instructions are now available on processors supporting Intel EM64T technology.
The relative address is contained in a dword which is part of the instruction. When using this type of addressing, the processor adds three values: a the contents of the dword containing the relative address b the length of the instruction and c the value of RIP the current instruction pointer at the beginning of the instruction.
The resulting value is then regarded as the absolute address of the data and code to be addressed by the instruction. Since the relative address can be a negative value, it is possible to address data or code earlier in the image from RIP as well as later. Since relative addressing cannot address outside this range, this is the practical size limit of bit images. Generally here are the rules which govern whether or not an instruction uses RIP-relative addressing:- Addresses in data cannot use RIP-relative addressing since the value of RIP cannot be known at the time when those addresses are set.
Instead, an absolute address for insertion is calculated at link-time. So for example the following instructions do not use RIP-relative addressing but instead use absolute addresses:- Note that in practice, the absolute address is contained in a dword and not in a qword. This is why in the above examples data and code addresses can be contained within a dword data declaration. This restriction is feasible because the practical image size is limited to 2GB anyway because of the restrictions imposed by RIP-relative addressing.
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