Another HP16 emulation

Ladybug more user friendly, if less versatile, HP16 module than the fully-featured HP16 module by Angel Martin. Both have their uses, but for a simple calculator for bit-banging while writing 6502 assembly code Ladybug does everything, with a less convoluted User Interface.

• A “CMP” function akin to 6502 - sets flags in the same way but doesn't change the register(s)
• Status Flags : C, Z, N and V equivalent to 6502 flags and set in the same way after various operations.
  • Flag 0 = Zero Z
  • Flag 1 = Sign N
  • Flag 3 = Carry C
  • Flag 4 = Overflow V
• 2's-complement mode is set with Flag 2
• Leading Zeros display is set with Flag 5

• Word Size is set with Shift+R/S
• Windowing is selected with .
• Bits can be set and reset and tested with Shift+4, Shift+5 and Shift+6

• Boolean Operations on values in X and Y registers
  • AND Shift+1
  • OR Shift+2
  • XOR Shift+3

• NOT Shift+CHS (invert each bit, on the value in the X register)

• Shift and Rotate functions are conveniently accessible - see Overlay picture above - without delving into menus or launchers

— John Pumford-Green 23/09/22 13:40

• ladybug.pdf
• https://github.com/hth313/ladybug/releases