@ Shift by zero.
SSSTN           | PUSH +1
SSSSN           | PUSH 0
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Shift by one, positive sign extension.
SSSTSN          | PUSH +2
SSSTN           | PUSH +1
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Shift by four, positive sign extension.
SSSTSSSSN       | PUSH +16
SSSTSSN         | PUSH +4
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Shift by one, negative sign extension.
@ -9223372036854775805 = 1000000000000000000000000000000000000000000000000000000000000011
@ -4611686018427387903 = 1100000000000000000000000000000000000000000000000000000000000001
SSTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTSTN | PUSH -9223372036854775805
SSSTN           | PUSH +1
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Shift by four, negative sign extension
@ -9223372036854775638 = 1000000000000000000000000000000000000000000000000000000010101010
@ -576460752303423478  = 1111100000000000000000000000000000000000000000000000000000001010
SSTSTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTTSTSTSTTSN | PUSH -9223372036854775638
SSSTSSN         | PUSH +4
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Test for special case: rshift(-1) = -1
SSTTN           | PUSH -1
SSSTN           | PUSH +1
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ Shift a single 1 in the MSb into all ones
SSTTSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSN | PUSH -(2^63)
SSSTTTTTTN      | PUSH +63
NSTTSTTSSN      | JSR > 101100 (rshift)
NSTTTTTSTN      | JSR > 111101 (debug:printsignednumber)

@ All done.
NNN             | DIE

#include <logic.pvvs>
#include <debug.pvvs>