HP Nanoprocessor code to determine the number of days in a month

days-in-month

d0  STR-0     Store the next byte (7) in register 0.
07
0c  SLE       Skip two instructions if accumulator <= register 0.
03  DED       Decrement the accumulator in decimal mode
5f  NOP       No operation
d0  STR-0     Store the next byte (0x31) in register 0
31
30  SBZ-0     Skip two instruction bytes if accumulator bit 0 is zero
81  JMP-1     Jump to 0x1c9 (end of this code block)
c9
a1  CBN-1     Clear accumulator bit 1
d0  STR-0     Store the next byte (0x30) in register 0
30
0f  SAN       Skip two instruction bytes if accumulator not zero
d0  STR-0     Store next byte (0x28) in register 0
28