The flag set and test routines 

THE 'SIGNAL ..' SUBROUTINES
These subroutines are used to signal various states of the +D. The corresponding test
routines are located from #161C and onwards. Clearing is done by loading 0 into FLASG3,
resetting all flags at once. 

15F4 SIGN_0     RST  #18,F_ADDR
15F5            SET  0,(HL)
15F7            POP  HL
15F8            RET

15F9 SIGN_1     RST  #18,F_ADDR
15FA            SET  1,(HL)
15FC            POP  HL
15FD            RET

15FE SIGN_2     RST  #18,F_ADDR
15FF            SET  2,(HL)
1601            POP  HL
1602            RET

1603 SIGN_3     RST  #18,F_ADDR
1604            SET  3,(HL)
1606            POP  HL
1607            RET

1608 SIGN_4     RST  #18,F_ADDR
1609            SET  4,(HL)
160B            POP  HL
160C            RET

160D SIGN_5     RST  #18,F_ADDR
160E            SET  5,(HL)
1610            POP  HL
1611            RET

1612 SIGN_6     RST  #18,F_ADDR
1613            SET  6,(HL)
1615            POP  HL
1616            RET

1617 SIGN_7     RST  #18,F_ADDR
1618            SET  7,(HL)
161A            POP  HL
161B            RET

THE 'TEST ..' SUBROUTINES
These subroutines are used to test the various states of the +D system.

161C TEST_0     RST  #18,F_ADDR
161D            BIT  0,(HL)
161F            POP  HL
1620            RET

1621 TEST_1     RST  #18,F_ADDR
1622            BIT  1,(HL)
1624            POP  HL
1625            RET

1626 TEST_2     RST  #18,F_ADDR
1627            BIT  2,(HL)
1629            POP  HL
162A            RET

162B TEST_3     RST  #18,F_ADDR
162C            BIT  3,(HL)
162E            POP  HL
162F            RET

1630 TEST_4     RST  #18,F_ADDR
1631            BIT  4,(HL)
1633            POP  HL
1634            RET

1635 TEST_5     RST  #18,F_ADDR
1636            BIT  5,(HL)
1638            POP  HL
1639            RET

163A TEST_6     RST  #18,F_ADDR
163B            BIT  6,(HL)
163D            POP  HL
163E            RET

163F TEST_7     RST  #18,F_ADDR
1640            BIT  7,(HL)
1642            POP  HL
1643            RET