Mixed C and Assembly

By Justin Kim

Mixed C and Assembly

• Set-up – Create Project and Gather Essential Files

• Strategy and Method – Assigning Tasks and How to Mix Languages

• Implementation – Apply Methods to the Serial to Parallel Lab

• Improvements – Minimize Code and Include Other Capabilities

Set-up• Create a New Project named MixedC and a c-file titled

MixedC.c (Refer to the Blink Lab Instructions from the EE-347 website.)

• Go to the EE-346 website and download AmazingLab, LabC, and sketch_shiftOut_16bit. Extract the following documents from the respected files:– AmazingLab spi.inc – LabC m328Pdef.h– sketch_shiftOut_16bit sketch_shiftOut_16bit.c

• Change the spi.inc document to a .S file (spi.S) and move to the MixedC Project File. Move the m328Pdef.h to the MixedC Project File as well. Copy the code from the sketch_shiftOut_16bit.c document and paste it into the MixedC.c document.

• Add all header files and .c files from C:\arduino-0015\hardware\cores\arduino to the MixedC Project File.

Strategy and Method

• Determine the operations needed• Understand the strengths of each

language• Figure out how to execute goals with each

language• Divide the tasks between the C functions

and the assembly subroutines.• Learn to globalize subroutines, use proper

syntax for the specific compiler, and pass parameters between each language.

Implementation• Imitate the Serial to Parallel Lab by Mixing

C and Assembly• Learn the GCC syntax• Use C as the main program and Assembly

to send the information to the displays• Globalize the subroutines, use correct

syntax, and pass a parameter (a byte) from C to Assembly using mask and register 24

• Delete or Comment out any unnecessary code.

Changes to the C Code

Original Code New Code

Changes to the C Code

Original Code New Code

*Comment out shiftOut and blinkAll entirely

Changes to the C Code

Original Code New Code

Changes to the Assembly Code

Original Code New Code

Changes to the Assembly Code

Original Code New Code

Improvements

• Minimize spiTx• Incorporate blinkAll• Pass Parameter from Assembly to C:

• EE-346 website – Labs and References

http://www.cecs.csulb.edu/~hill/ee346/

• EE-347 website – Labs and References

http://www.cecs.csulb.edu/~hill/ee347/

• Equate Statement Syntaxhttp://www.experts-exchange.com/Programming/Languages/Assembly/Q_23559266.html

• Examples of Mixed C and Assembly

http://people.msoe.edu/~barnicks/courses/CE-2800/documents/Mixing%20C%20and%20assembly%20language%20programs.pdf

References