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Re: [Qemu-devel] [PATCH 26/60] AArch64: Add ADR instruction emulation
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From: |
Michael Matz |
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Subject: |
Re: [Qemu-devel] [PATCH 26/60] AArch64: Add ADR instruction emulation |
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Date: |
Wed, 20 Nov 2013 15:40:53 +0100 (CET) |
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User-agent: |
Alpine 2.00 (LNX 1167 2008-08-23) |
Hi,
On Tue, 19 Nov 2013, Claudio Fontana wrote:
> > + uint64_t imm;
> > + uint64_t base;
> > +
> > + imm = get_sbits(insn, 5, 19) << 2;
> > + imm |= get_bits(insn, 29, 2);
>
> does this work with negative values?
Yes. get_sbits returns a sign extended (32bit) int, the shift doesn't
change that, the conversion to uint64_t first sign extends to 64bit and
then converts to unsigned (conceptually). From then on it's an unsigned
value (with high bits set when input was negative), but two complement
arithmetic makes that irrelevant.
Ciao,
Michael.