Necessary to save used registers in assembly ?

I am using assembly language routines called from C code. Within the assembly routines, is it necessary to save the registers used? Ex: MY_ASM_ROUTINE: PUSH ACC ; necessary ? CLR A ; overwrite...
Necessary to save used registers in assembly ?

I am using assembly language routines called from C code. Within the assembly routines, is it necessary to save the registers used? Ex: MY_ASM_ROUTINE: PUSH ACC ; necessary ? CLR A ; overwrite...
Is the 'S' necessary in the asm code?

Hi, Before I write some Cortex A8 assembly code, I review some disassembly code of a small C program. In the following snippet, I don't understand the necessity of 'S' in ADDS. In fact, I don't see the...
Is the 'S' necessary in the asm code?

Hi, Before I write some Cortex A8 assembly code, I review some disassembly code of a small C program. In the following snippet, I don't understand the necessity of 'S' in ADDS. In fact, I don't see the...
Is PORESETn necessary to make a debugger work correctly?

According to the Cortex-M3 trm r2p0(Issue H), Cortex-M3 has 3 reset input signals, PORESETn, SYSRESETn, and DAPRESETn. Now I am thinking about a SOC with SW-DP and thinking of reducing the number of...