Thank for your reply.
Whats the assembler are you using? do you means:Reads51 V3.x absolute assembler and Reads51 V4 relative assembler or some thing else?
on the options => tools chain/target option: if i select Reads51 V4 relative assembler and run my code, i got errors. but if i select Reads51 V3.x absolute assembler and run/build the code, i do not get errors.
From the above, I learned that Reads51 V3.x absolute assembler is to be used if your target is not a real embedded circuit board but instead is PC chip simulator, and the output is SimIO.
please correct me for the above if i am wrong. i am just learning.