Wikipedia gives some background and useful links. This page shows:. One of its distinctive features is support for two instruction sets: the ARM set with bit instructions, and the Thumb set with bit instructions. The former is considered to give faster but larger code, while the latter gives slower but smaller code.
|Published (Last):||15 December 2006|
|PDF File Size:||15.80 Mb|
|ePub File Size:||18.32 Mb|
|Price:||Free* [*Free Regsitration Required]|
Wikipedia gives some background and useful links. This page shows:. One of its distinctive features is support for two instruction sets: the ARM set with bit instructions, and the Thumb set with bit instructions.
The former is considered to give faster but larger code, while the latter gives slower but smaller code. The processor can switch between the two instruction sets at run-time, using the BX "branch and exchange" instruction to change from ARM state to Thumb state or vice versa. Calling a Thumb subprogram from ARM state, or vice versa, is known as "interworking". Some compilers generate "interworking" code by default, others may need a specific compilation option or directive to do so.
Several different companies produce different devices chips which execute the basic ARM7 instruction set. Some devices support Thumb. However, memory access times may differ between devices, both for code and data accesses. Those devices that have on-chip flash memory for code often use some kind of flash accelerator hardware to speed up the code fetches from the flash, which otherwise would become a bottleneck at high clock frequencies.
The accelerator hardware can be a simple wide fetch, for example reading bits of flash contents at a time, or it can include a concurrent wide prefetch, or even cache-like buffers that may make the fetch time and thus the overall execution time history-dependent and hard to predict. In this sense, it can be considered a prototype implementation.
The analysis of computation and data flow is based on bit numbers. The interaction aliasing of bit memory accesses and accesses to bit or 8-bit parts of memory words is not modelled. For BX the new state is defined by the least significant bit of the branch target address. On return from an SWI handler the caller's state is restored. However, a BX takes the branch target address from a register, so it is in principle a dynamic value.
If the BX is used only to change state, the target address is very probably a constant that can be deduced from the analysis, giving an automatic analysis of both the branch and the change of state.
Coprocessors exist for floating-point computations and other kinds of computations. All results of coprocessor computations are modelled as unknown opaque values. For example, the ARM7 instruction that stores coprocessor registers into memory words is modelled as storing unknown values into these memory words.
No caches, flash-memory buffers, or other dynamic accelerators are modelled at present. Bound-T for ARM7 at present models only the basic, pipeline execution time.
Thus, its execution-time analysis will be too optimistic for any ARM7 device that has wait states for memory accesses. The stack-usage analysis, on the other hand, is not device-dependent. Many cross-compilers for the ARM7 exist, both "free" ones and commercially licensed ones.
In principle Bound-T is able to analyse machine code from any compiler. However, different compilers create executable files in different formats, and Bound-T is not able to read all possible formats. Moreover, different compilers may generate different kinds of symbolic debugging information, which Bound-T uses to communicate with the user in source-level terms. Finally, each compiler may generate its own idiomatic instruction sequences, some of which need special analysis methods, and has its own set of library subprograms, some of which may not follow the ordinary parameter-passing and stack-handling rules and therefore need special attention in Bound-T.
For these reasons, Bound-T often needs to adapt its analysis to the compiler that generated the code to be analysed. However, this does not mean that Bound-T will correctly analyse all code from these compilers, for all source programs.
If your compiler is not listed in this table, please contact Tidorum to ask if your compiler is supported, or can be supported. ARM7 Application Note.
See also the general Bound-T manuals. Describes how Bound-T reads and analyses executable programs in the Intel Hex file format.
What does "TDMI-S" stand for?
This generation introduced the Thumb bit instruction set providing improved code density compared to previous designs. All these designs use a Von Neumann architecture , [ citation needed ] thus the few versions containing a cache do not separate data and instruction caches. Some ARM7 cores are obsolete. Subsequent cores included and enhanced this support. It is a versatile processor designed for mobile devices and other low power electronics.
E5900B-300 ARM 7, ARM 9, and ARM 9 TDMI Emulation Probes
T : supports both ARM bit and Thumb bit instruction sets. An instruction set is a list of binary patterns, or "opcodes", which represent the different logical operations a processor can perform. Software programs can be written at different levels of abstraction, from low level "assembly code" where each written instruction typically maps onto one corresponding opcode, up to high level languages where the written program source code needs to be processed by a compiler which typically converts each written instruction into a whole sequence of opcodes. The original ARM instruction set consists of bit opcodes, so the binary pattern for each possible operation is four bytes long.
The meanings of 'TDMI-S', 'JZF-S' and 'T2F-S'