GraphNCalc83 FAQ

Question: Where are the ZOOM, CALC and TRACE keys?

Answer: They are located at the bottom of the graph screen. Touch the GRAPH key to view the graph screen. Touch the graph of a function to select it. Swipe your finger over a selected function to TRACE. The CALC button will display when you select a function. Touch the background to unselect a function.

Question: The display is showing all answers rounded to an integer. How do I get a decimal display?

Answer: Touch the MODE key, then touch the Float button. Do NOT move the slider bar next to the Float button.

Question: How do reset the calculator?

Answer: Touch 2nd MEM (on the + key), then touch Reset… and select Defaults…

Question: How do I get tech support or report a problem?

Answer: Touch ?? then touch the “ask a question” button.

Question: How do I change the number of decimal places?

Answer: Touch the MODE button and move the slider bar in the DISPLAY section of the MODE screen to the number of decimal places you want to view. Touch the Float button to change to floating point display.

Question: Can I send programs or data from GrafNCalc83 on my iPhone to my friend’s iPhone?

Answer: Touch 2ND, SHARE and select a data type from the list and then select the items to send. Then touch the action button at the top of the screen. You can send by Mail, Message or AirDrop.

Question: Does GraphNCalc83 have a Z80 emulator? Does it require a copy of the TI-83 ROM?

Answer: GraphNCalc83 is written in objective-C compiled for Arm processors. It does not use a TI-83 ROM image and there is no Z80 emulator included. Since there is no Z80 emulator included, GrafNCalc cannot execute TI-83 assembly programs.

Question: How does GraphNCalc83 run so fast?

Answer: The TI-83 was first released in 1996 using a 6 MHz Z80 processor. Current versions of the TI-83 use a 15 MHz Z80. The Z80 processor computes with 8 bits at a time and only has integer instructions. All floating point calculations on the Z80 processor are done using slow floating point emulation subroutines. The Arm processors included in the iPhone run at over 1000 MHz and process 32 or 64 bits at a time. The Arm processors include hardware instructions to directly compute in floating point. The basic hardware in the iPhone thus runs more than 300 times faster than the fastest TI-83. GraphNCalc83 is written in objective-C and compiled to run native code on Arm processors so it fully leverages the iPhone computing resources. In addition, GraphNCalc83 uses modern mathematics libraries to greatly accelerate the computation of many functions using parallel processing and the floating point units of the iPhone graphics processors. As a result, GraphNCalc83 can smoothly scroll and scale full screen color graphs that take minutes to render on a TI-83. BASIC programs run faster on GrafNCalc than equivalent assembly programs on a TI-83.

Question: Can I run TI-83 assembly programs on GraphNCalc83?

Answer: No.