ref: d3da2e1b89f30f404c3d11053680098f1b7bf677
dir: /os/boot/puma/ureg.h/
typedef struct Ureg { uint r0; uint r1; uint r2; uint r3; uint r4; uint r5; uint r6; uint r7; uint r8; uint r9; uint r10; uint r11; uint r12; uint r13; uint r14; uint link; uint type; uint psr; // uint sp; uint pc; } Ureg;