Move bit_count constants from examples/ARM/v7 to wordsTheory.

revert some of 0fc7587: allow add_persistent_funs of other consts

change interface to add_persistent_funs (#73) and fix more calls

The new interface takes a list of strings naming theorems.
(The old interface took a list of (string * thm) pairs.)
The new way better ensures consistency of theory development and theory
load behaviour: you can no longer pass a name with a theorem that isn't
actually saved under it.

Theorems are looked up with DB.theorem, or failing that, DB.definition
or DB.axiom.

Alas, I found more examples using add_persistent_funs to add theorems in
ancestor theories. Rather than modify the ancestor theories, I have
opted to make the offending theories save the theorems they want to add
to computeLib themselves so they have a name in the current theory to
pass to add_persistent_funs.

If this behavior was appropriate for patricia too (da47401) change it.
Alternatively, if the ancestor theories should have exported those
things for computeLib anyway, search this commit for new instances of
"save_thm" to see what needs fixing.

Minor fixes.

Adopt ML-style syntax for case expressions and use freed up "||" for bitwise-or. See issue #24.

Correct spelling. Also move location of SInt and UInt.

Move some definitions from arm_opsem to arm_coretypes.

Added word_sign_extend to src/n-bit.

Change the specification wrt interrupt masking. The function arm_next no
longer masks interrupts -- this is instead left to the level above,
e.g. arm_run.

Other changes include more checking of step theorems in selftest. Also made use
of tools in updateLib.

A few changes:

- Make use of the new zDefine
- Moved some theorems from arm_stepTheory to arm_opsemTheory and
arm_coretypeTheory, e.g. change_processor_state_thm and encode_psr_bit
- Changed some instruction specifications -- moving the call to
current_mode_is_user_or_system.
- Remove unwanted application of WORD_ARITH_ss in arm_stepLib. This was
inadvertently added in a previous check-in.

Update that adds support for ThumbEE.

/* From the ARM reference...

ThumbEE

Is a variant of the Thumb instruction set that is designed as a target for
dynamically generated code. It is:
* a required extension to the ARMv7-A profile
* an optional extension to the ARMv7-R profile. */

Added support for hardware interrupts: reset, fiq and irq. This adds an extra
argument to the next state functions, i.e. we now have

arm_next : iiid -> HWInterrupt -> unit M

and

ARM_NEXT : HWInterrupt -> arm_state -> arm_state option

In the absence of an interrupt, the previous behaviour is obtained with

ARM_NEXT NoInterrupt : arm_state -> arm_state option

The single-step behaviour for interrupts can be obtained with

armLib.arm_step "" "reset" (* ARM_NEXT HW_Reset *)
armLib.arm_step "" "irq" (* ARM_NEXT HW_Irq *)
armLib.arm_step "" "fiq" (* ARM_NEXT HW_Fiq *)

There has also been some minor tidying-up to the code.

Tweak definition of encode_psr and remove some unused code.

A few changes:

1. Make it clear that the ARMv7-M profile is not properly supported (yet).
2. Fix for EmitML script (following changes to memory).
3. Fixed parsing/encoding for 16-bit Thumb MOV (register) instruction.
4. Fixed bugs in model for BFI, SSAT and SSAT16.

Changes to the memory, to conform with the approach that Magnus explored in
ARM/experimental.

The memory now has type :address -> word8, instead of :address -> word8 option.
Accesses are recorded in a component state.accesses : memory_access list.

Word slice "<>" has been replaced with "''".

A new Monadic ARM instruction set specification. Covers all current ISA
versions i.e. ARMv4 to ARMv7.

Doesn't cover the ThumbEE, VFP and Advanced SIMD extensions. Also doesn't
model hardware interrupts - these will be added at a later date.

To use the armLib tools, Moscow ML users will likely have to apply the patch to
avoid the Chr exception.
<http://hol.sourceforge.net/mosml-chr-instructions.html>