0: R0: 0x00
1: R1: 0x01
2: R2: 0x02
3: R3: 0x03
4: R4: 0x04
5: R5: 0x05
6: R6: 0x06
7: R7: 0x07
8: R8: 0x08
9: R9: 0x09
10: R10: 0x0a
11: R11: 0x0b
12: R12: 0x0c
13: R13: 0x0d
14: R14: 0x0e
15: R15: 0x0f
16: XPSR: 0x10
17: MSP: 0x11
18: PSP: 0x12
19: RAZ: 0x13
20: CFBP: 0x14
21: APSR: 0x15
22: EPSR: 0x16
23: IPSR: 0x17
24: PRIMASK: 0x18
25: BASEPRI: 0x19
26: FAULTMASK: 0x1a
27: CONTROL: 0x1b
28: BASEPRI_MAX: 0x1c
29: IAPSR: 0x1d
30: EAPSR: 0x1e
31: IEPSR: 0x1f