ldmea vs ldmfd

Sorry, what is difference between ldmea and ldmfd? I'm just a student who want to study arm assembly more haha... Thank You
warnings

upon building my application in keil I get following warning *** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL
warnings

Hi, Why do I get these warnings? Are these warnings critical, and can they get the program to crash? assembling STARTUP.A51... linking... *** WARNING L16: UNCALLED SEGMENT, IGNORED FOR...
Warning Level

Hi, someone know how to change the warning level in uVision? Is there a way to change the warning level like in VC++? Or they are fixed and varies only with the optimization level? look at: ...
Warning: L6776W:

program crashs in debugging and it doesn't run to main !! linking... .\Objects\ELKREM.axf: Warning: L6776W: The debug frame in .debug_frame(spark_wiring_string.o) does not describe an executable...