FUNCTION::REGISTER(3stap)

💖 FUNCTION::REGISTER 💖

okay bestie, welcome to function::register from the Context Functions part of the SystemTap Tapset Reference (yes that's the manual we're in, hi 👋).

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✨ NAME ✨

function::register — it hands you back the signed value of whichever CPU register you name. that's it. that's the whole job. and it eats. 👑

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🌸 SYNOPSIS 🌸

register:long(name:string)

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🎀 ARGUMENTS 🎀

• name — the name of the register you want the value of. just the name. drop it in, get your number back, no cap. 💅

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🦋 DESCRIPTION 🦋

so here's the vibe: this returns the value of the named CPU register as it was saved when the current probe point was hit. like, the frozen-in-amber snapshot of that register at that exact moment. iconic. ✨

and if the register happens to be 32 bits? it gets sign-extended to 64 bits. the glow-up is automatic. 💖

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💜 i386 — the names it recognizes 💜

for the i386 architecture, these are the recognized names. (name1/name2 means name1 and name2 are alternative names for the same register — like two stan accounts for one person, iykyk):

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.

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🌈 x86_64 — the names it recognizes 🌈

for the x86_64 architecture, here's the whole roster:

• 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

not me pointing out that edx shows up twice in that 32-bit list — that's literally what the page says, so we keep it exactly as-is. no editing the source material, periodt. 📝

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🧚 powerpc — the names it recognizes 🧚

for powerpc:

r0, r1, ... r31, nip, msr, orig_gpr3, ctr, link, xer, ccr, softe, trap, dar, dsisr, result.

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🍓 s390x — the names it recognizes 🍓

for s390x:

r0, r1, ... r15, args, psw.mask, psw.addr, orig_gpr2, ilc, trap.

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💀 AArch64 — the names it recognizes 💀

for AArch64:

x0, x1, ... x30, fp, lr, sp, pc, and orig_x0.

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👑 SEE ALSO 👑

• tapset::registers(3stap) — go read it, bestie, it's the whole register tapset 🫶

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okay that's the whole page!! mwah 💋 this was SystemTap Tapset Reference, version whatever-we-got, dated September 2026 — so if you're reading this in the future, hey, slay, you're literally so on time. 🌟 byeeee 💖🌸✨