_EXEC - execute machine instructions.

Usage:

B:
   q_reg = _exec(aval, qval, inst1, inst2, ...);

C:
   int _exec(int aval, int qval, int inst1, ...);

Where:

aval: is a value that _EXEC loads into the A register.
qval: is a value that _EXEC loads into the Q register.
inst1, inst2, ...: is a sequence of machine instructions. Each instruction is specified as an integer whose value is equal to the hardware's representation of the desired machine instruction.
q_reg: is the value of the Q register after the given instructions have been executed.

Description:

_EXEC loads the A and Q registers with specified values, then executes a specified set of machine instructions. The result of _EXEC is the value that the Q register has after the instructions have been executed. You can obtain the value of the A register by executing

var = .null();

immediately after the call to _EXEC. This stores the A register value in "var".