I am trying to do the ASM instruction DCD 0xf7f0a000 in ARM C code.
The below methods I tried and errors I got:
__asm("DCD 0xf7f0a000");
Error : #3061: unrecognized instruction opcode
__asm
{
MOV r0,=0xf7f0a000
MOV r1,{r0}
}
Error: Implicit physical register R0 should be defined as a variable.
Error: Implicit physical register R1 should be defined as a variable.
Update:
ARM Compiler Version: ARM Compiler 5.06 update 6
PS: I am trying to generate an exception by doing undefined operation.
ARMCC has very good quality documentation available from the vendor.
You did not specify the version of your ARMCC, apparently things have changed since I used it (~15 years ago).
You need to study this if you want to use inline assembly (again - if this fits your compiler version): https://developer.arm.com/tools-and-software/software-development-tools/legacy-tools/ds-5-development-studio/resources/tutorials/using-inline-assembly-to-improve-code-efficiency
Note: Register names in inline assembly code are treated as C or C++ variables. They do not necessarily relate to the physical register of the same name. In our C code, we use the variable names r5 and r6 for our operands, but the actual registers used are r1 and r2.
Inline __asm can be very cumbersome to use unless you perfectly understand what you're doing. It is usually much easier to place your assembly code into a separate file. (Used to have .asm extension back then, not sure about now).
PS: I am trying to generate an exception by doing undefined operation.
As far as I can see, you are trying to write into invalid address, this is not the same as 'undefined operation' and you can do this from C using an invalid pointer, no need for asm at all:
int *a;
a = 0xf7f0a000;
*a = 2019;
Another edit: And finally answering the actual question in the title :) I don't think you can. DCD is not an opcode, it is an assembler directive, it can't be used within __asm block (inline assembly), it can only be used in the 'real' assembly language code.