We are running a survey to help us improve the experience for all of our members. If you see the survey appear, please take the time to tell us about your experience if you can.
I use KeilC uVision4 for 89C51 MCU. By "Inline ASM", i can easily direct write value to R7 register, like this :
#pragma ASM MOV R7, #10 #pragma ENDASM
But now, there are some reason that i have to write to R7 register direct from C (not from inline ASM), eg:
R7 = 10;
Of course, the C compiler does not understand R7 as MCU Register (not Inline ASM).
-> Is there anyway to solve this problem. Please help me if anyone know, thanks a lot !
if at least 2 experienced people are telling you DON'T DO IT! and you refuse and insist on doing it your way, when it is clear even to a non-C51 guy like me that what you are doing is plain wrong, then you are no less than a ticking bomb. have you even considered that your "time gain" will be nullified by the hoops the processor will have to jump through in order to compensate for your macroed assembly...?
.. I will repeat
DO NOT MESS WITH REGISTERS IN INLINE ASM
you are hellbent on doing it this way and in a while you will come crying here "why does this not work" when you run into a conflict between your inline and the compilers register usage which legally can be any which way and be changed at any time.
Erik
Actually, that's about the one thing that's not at issue!
We're talking about software delays - so wasting processor cycles is the object of the exercise!
The problem is that the proposed macro approach is so horribly cumbersome and error-prone - especially when doing it as an assembler module is so clean, simple, and easy!
to compensate for his register usage in the middle of it
I merely trying to convince the OP (without much success, I guess...!) of the cascade negative impact his design will have - include impairing other piece of software that are supposed to have "well-known behavior".
.. to tell a young truly modern person not to write unmaintainable code.
today, the typical shop has 5 testers for each programmer, so who gives an iota if code is good, if it fails, the teaters will catch it.
Always worth leaving the accidental on purpose error in to test whether the teaters are awake ;)