Register

A simple utility to safely manipulate registers with zero overhead.\

Why

I wanted to make a super simple utility with these features:

• Just a single reinterpret_cast<> for N registers, useful in case of future safety certifications
• Operations don't touch the stack. Zero stack used!
• Any bitmask calculated at compile time
• Errors like setting the bit 17 of a 16 bit registers caught at compile time
• The address of a given register is part of its type, no extra memory required to store any pointer.
• Last but not least: no macros

Example

In this section, a few examples with the generated assembly.
Compiler used: ARM gcc 11.2.1 (none), flags -std=c++14 -O3

#include <mabe/register.hpp>

// Lets define a couple of registers
namespace my_regs {
using reg32 = RegU32<0x1000>;
using reg8 = RegU8<0x1004>;
}

Setting all bits (32 bit reg)

my_regs::reg32::set_all();

ARM assembly:

mov r3, #4096 ; 0x1000
mvn r2, #0
str r2, [r3]

Setting bits 2,3,31 (32 bit reg)

my_regs::reg32::set_bits<2, 3, 31>();

ARM assembly:

mov r2, #4096            ; 0x1000
ldr r3, [r2]
orr r3, r3, # 2147483636 ; 0x8000000c
str r3, [r2]

Clearing bit 1 (8 bit reg)

my_regs::reg8::clear_bit<1>();

ARM assembly:

mov	r2, #4096	; 0x1000
ldrb	r3, [r2, #4]
and	r3, r3, #253	; 0xfd
strb	r3, [r2, #4]

!!! Note !!!

This project is still work in progress. Any feedback is appreciated.