---
name: "function::register"
section: "3stap"
platform: "linux"
package: "systemtap-doc"
version: "5.1-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/function::register"
---

# function::register(3stap)

Return the signed value of the named CPU register

## NAME

function::register - Return the signed value of the named CPU register

## SYNOPSIS

```
    register:long(name:string)
```

## ARGUMENTS

*name*

Name of the register to return

## DESCRIPTION

Return the value of the named CPU register, as it was saved when the current probe point was hit. If the register is 32 bits, it is sign-extended to 64 bits.

For the i386 architecture, the following names are recognized. (name1/name2 indicates that name1 and name2 are alternative names for the same register.) eax/ax, ebp/bp, ebx/bx, ecx/cx, edi/di, edx/dx, eflags/flags, eip/ip, esi/si, esp/sp, orig\_eax/orig\_ax, xcs/cs, xds/ds, xes/es, xfs/fs, xss/ss.

For the x86\_64 architecture, the following names are recognized: 64-bit registers: r8, r9, r10, r11, r12, r13, r14, r15, rax/ax, rbp/bp, rbx/bx, rcx/cx, rdi/di, rdx/dx, rip/ip, rsi/si, rsp/sp; 32-bit registers: eax, ebp, ebx, ecx, edx, edi, edx, eip, esi, esp, flags/eflags, orig\_eax; segment registers: xcs/cs, xss/ss.

For powerpc, the following names are recognized: r0, r1, ... r31, nip, msr, orig\_gpr3, ctr, link, xer, ccr, softe, trap, dar, dsisr, result.

For s390x, the following names are recognized: r0, r1, ... r15, args, psw.mask, psw.addr, orig\_gpr2, ilc, trap.

For AArch64, the following names are recognized: x0, x1, ... x30, fp, lr, sp, pc, and orig\_x0.

## SEE ALSO0

[*tapset::registers*(3stap)](/tapset::registers/3stap.md)