I've noticed that the following definitions generate different data results. Perhaps, I'm overlooking something. #define TEMP (*(unsigned char xdata *) 0x10F0)) unsigned char xdata sutton2, *sutton; unsigned char xdata * xdata sutton3; sutton = &TEMP; sutton3 = &TEMP; sutton2 = TEMP; If XDATA location 0x10F0 has 0x35, then the following compilation occurs: 'sutton' has the value X:10F0, which is correct. 'sutton2' has the value 0x35, which is correct. 'sutton3' has the value D:10F0, which is not correct. To complicate things, if I swap the 'sutton2' and 'sutton' declarations to: unsigned char xdata *sutton, sutton2; then 'sutton' has the value D:10F0, which is not correct. There is no DATA location 10F0, therefore garbage is the result. The source code generated for *sutton being first in the declaration list is a 2 byte XDATA pointer, which points to the DATA area. If *sutton is not the first declaration in the list, it is a 3 byte pointer (which works correctly) that points to XDATA. Anyone know what the problem is and why the sutton3 declaration listed above does not force the compiler to generate a pointer that points to XDATA? Thanks Sutton Mehaffey Lookout Portable Security sutton@lookoutportablesecurity.com
The following code works great for me.: C Compiler: C51.exe V6.20c
#include <intrins.h> #define TEMP (*(unsigned char xdata *) 0x10F0) void main ( void ) { unsigned char xdata *sutton, sutton2, xdata *sutton3; sutton = &TEMP; sutton3 = &TEMP; sutton2 = TEMP; _nop_(); }
I ran the exact same code and sutton and sutton3 contain D:10F0 and sutton2 is correct and holds the value from X:10F0. So, I don't know the problem. Maybe an emulator problem, which is what I am using to view results.
What version of the compiler are you using? Maybe there is a difference in mine. I'm using 6.01.
Yup! I'm running the lastest version. C Compiler: C51.exe V6.20c
Maybe an emulator problem, which is what I am using to view results. Which emulator are you using? Have you contacted the emulator vendor to see if they have updated software? Jon
View all questions in Keil forum