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I use the LPC1768 board and I want to copy a function from flash to RAM in runtime. I use the following code
void f() { int x=0; printf("%d\n",x); } void g() { int x=5; printf("Hello: g"); printf("%d\n",x); } int main(void) { char c; static void (*fnRAM_code)(void) = &f; int offset= (int)((long)g-(long)f); int i=0; int z=0; int *x; extern void uart0_init(void); unsigned char *pCodeStart = (unsigned char *)f;
uart0_init();
//(*fnRAM_code)();
//thump2 addresss /* Thumb 2 address */ pCodeStart = (unsigned char *)(((unsigned int)pCodeStart) & ~0x1); while (i < PROG_SIZE) { ProgRamSpace[i] = pCodeStart[i]; i++;
} (*fnRAM_code)(); fnRAM_code = (void(*)(void))(ProgRamSpace); (*fnRAM_code)(); }
But when I access the new address of the function I get the following error access violation at 0x100000018: no execute /read permision. Can anyone provide a solution for this issue Best regards, George
The scatter file is the following ; ************************************************************* ; *** Scatter-Loading Description File generated by uVision *** ; *************************************************************
LR_IROM1 0x00000000 0x00080000 { ; load region size_region ER_IROM1 0x00000000 0x00080000 { ; load address = execution address *.o (RESET, +First) *(InRoot$$Sections) .ANY (+RO) } RW_IRAM1 0x10000000 0x00008000 { ; RW data .ANY (+RW +ZI) } }
Hello, Regarding the Hard Fault exception. This took place because of the LSP of PC was 0. I fixed this . And now the only issue that I have is with the permision writes. I went throught the datasheet of LPC1768 and I noticed that the region 0x10004000 has exec rights. The program counter has LSB 1. I attached the scatter file again LR_IROM1 0x00000000 0x00080000 { ; load region size_region ER_IROM1 0x00000000 0x00080000 { ; load address = execution address *.o(RESET, +First) *(InRoot$$Sections) *.o(+RO) } RW_IRAM1 0x10000000 0x00004000 { ; RW data .ANY (+RW +ZI) } RW_IRAM2 0x10004000 0x00002000 { ; RW data *(section)
}
Regarding the scatter file the following memory mapping is generated for the variable ProgramRamToSpace
Execution Region RW_IRAM2 (Base: 0x10004000, Size: 0x00000040, Max: 0x00002000, ABSOLUTE)
Base Addr Size Type Attr Idx E Section Name Object
0x10004000 0x00000040 Data RW 137 section copytoram.o.
This variable includes function instructions. But its type is Data. Can i mark in someway this variable as thumb code type as the functions that are allocated in ROM. I read carefully your previous post and I think that the corrects instructions are saved in the buffer and the initial address of the function in the RAM is correct.
Thank you for your time
Best regards George