今天码代码的时候遇到这个warning，查了之后才发现，自己把定时器0也定在interrupt 0上了- -
特此转载。
nformation in this article applies to:
- C51 All Versions
SYMPTOMS
When linking your program, the linker responds the following warning:
WARNING L5: CODE SPACE MEMORY OVERLAP
CAUSE
This warning is caused by one or more code segments that overlap (reside at the same address). The warning message you receive should indicate the address range where the overlap occurred. The segments are typically absolute (interrupt service routines or buffers located at fixed addresses).
One common cause is two interrupt routines declared with the same interrupt vector. For example:
void ISR1 ( void ) interrupt 0 { } and void ISR2 ( void ) interrupt 0 { }
Note that the interrupt function names are different but the interrupt vectors are the same. This often happens when an interrupt routine is copied but the vector isn't changed.
RESOLUTION
Resolving this problem is usually very easy.
First, check the linker MAP file for the Code Memory Link Map.
LINK MAP OF MODULE: test (MAIN) TYPE BASE LENGTH RELOCATION SEGMENT NAME ----------------------------------------------------- . . . * * * * * * * C O D E M E M O R Y * * * * * * * CODE 0000H 0003H ABSOLUTE CODE 0003H 000CH UNIT ?C_C51STARTUP CODE 000FH 0001H UNIT ?PR?MAIN?MAIN CODE 0010H 0014H ABSOLUTE * OVERLAP * CODE 001BH 0003H ABSOLUTE CODE 0024H 0001H UNIT ?PR?ISR?MAIN
From here, you can locate all of the overlapping segments. Simply search for OVERLAP in the link map section of the map file. In this case, it appears an absolute segment from 10h-23h (14h bytes long) and another absolute segment from 1Bh-1Dh (3h bytes long) are overlapping each other.
An absolute segment 3 bytes long starting at address 0000h is the reset vector. Absolute segments 3 bytes long starting at address 0003h, 000Bh, 0013h, 001Bh, and so on are interrupt vectors. These point to the interrupt function (usually written in C). In this case, the absolute segment at address 001Bh is the interrupt vector for interrupt 3.
Next, determine where the absolute address comes from by checking the symbol table (from the linker MAP file). For example:
SYMBOL TABLE OF MODULE: test (MAIN) VALUE TYPE NAME ---------------------------------- ------- MODULE MAIN C:0000H SYMBOL _ICE_DUMMY_ C:000FH PUBLIC main C:0010H PUBLIC buf C:0024H PUBLIC ISR ------- PROC MAIN C:000FH LINE# 3 C:000FH LINE# 4 C:000FH LINE# 5 ------- ENDPROC MAIN
Here you can see that 0010h is buf from the MAIN module (main.c) and 0024h is ISR. If you take a look in the MAIN source file you'll see the problem:
int code buf[10] _at_ 0x10; void main (void) { } void ISR (void) interrupt 3 { }
In this case, buf is stored at address 0x10-0x23 and the ISR vector is at address 0x1B-0x1D. And, this is the overlapping memory.
MORE INFORMATION
- Refer to Warning L5 in the BL51 User's Guide.
- Refer to Warning L5 in the LX51 User's Guide.
