%edx -> SP_Reg
tabs -> spaces
Use named registers
Save/restore other crucial registers for safety
use ALTZP offset to avoid test/branch
refactor ALTZP switch to C
refactor 80COL switch to C
refactor ALTCHAR switch to C
refactor DHIRES,IOUDIS switches to C
refactor some softswitch query routines to C
refactor C3ROM,CXROM switches to C
Add a comment about suspect code
HACK around apparently problematic return from calling C

    * HACK ALERT!!! movl(%eax), %eax   --or--  movzbl(%eax), %eax
    * This pattern appears to be generated in some cases by the compiler.  It's not clear to me why it's a problem for
      the emulator (not a crash per se, but an emulation lock-up).
    * Current suspicion is that there are side-effects in the x86 flags from this instruction/indexing mode which are
      copied into the 6502 flags
    * Current sample code showing problem (and non-boot of emulator) is f785da40e986f8256d861a717c2f19312ce970f3
Complete refactoring VM routines to C
Use named registers
Work around an abort in mockingboard for now
Make opcode entry points globally linkable
Refactor CPU code

    * Moves cpu jump table, opcycles table, and others to C
    * Removes support for old/unused/deprecated nmos routines and tables
Tweak joystick x-axis

    * Seems to make S.R. play better and doesn't affect A.H.