From: Richard Henderson <rth@twiddle.net>
To: Claudio Fontana <claudio.fontana@huawei.com>, qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, claudio.fontana@gmail.com
Subject: Re: [Qemu-devel] [PATCH 07/26] tcg-aarch64: Use adrp in tcg_out_movi
Date: Mon, 24 Mar 2014 08:36:59 -0700 [thread overview]
Message-ID: <5330511B.3050501@twiddle.net> (raw)
In-Reply-To: <53303B93.2090206@huawei.com>
On 03/24/2014 07:05 AM, Claudio Fontana wrote:
>> > + /* Look for host pointer values within 4G of the PC. This happens
>> > + often when loading pointers to QEMU's own data structures. */
>> > + disp = (value >> 12) - ((intptr_t)s->code_ptr >> 12);
>> > + if (disp == sextract64(disp, 0, 21)) {
>
> nit.. for the check to be correct in all cases, the assumption here is that
> intptr_t is the same size as a signed target long; would a cast to
> tcg_target_long instead of intptr_t be "safer"?
>
I don't think so.
Gcc 4.9 supports an -m32 abi for aarch64. Suppose we were to compile qemu this
way. In that case tcg_target_long would be larger than intptr_t, and the cast
here would Werror. But leaving it intptr_t, we get a proper sign-extension
with type promotion to tcg_target_long, and the arithmetic will in fact work
like expected.
r~
next prev parent reply other threads:[~2014-03-24 15:37 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-15 2:48 [Qemu-devel] [PATCH 00/26] tcg/aarch64 improvements, part 3 Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 01/26] tcg-aarch64: Properly detect SIGSEGV writes Richard Henderson
2014-03-24 11:05 ` Claudio Fontana
2014-03-24 15:33 ` Richard Henderson
2014-03-24 11:45 ` Claudio Fontana
2014-03-24 12:17 ` Peter Maydell
2014-03-24 12:41 ` Peter Maydell
2014-03-24 15:27 ` Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 02/26] tcg-aarch64: Use intptr_t apropriately Richard Henderson
2014-03-24 12:12 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 03/26] tcg-aarch64: Use TCGType and TCGMemOp constants Richard Henderson
2014-03-24 12:52 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 04/26] tcg-aarch64: Use MOVN in tcg_out_movi Richard Henderson
2014-03-24 14:06 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 05/26] tcg-aarch64: Use ORRI " Richard Henderson
2014-03-24 14:06 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 06/26] tcg-aarch64: Special case small constants " Richard Henderson
2014-03-24 14:08 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 07/26] tcg-aarch64: Use adrp " Richard Henderson
2014-03-24 14:05 ` Claudio Fontana
2014-03-24 15:36 ` Richard Henderson [this message]
2014-03-26 9:34 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 08/26] tcg-aarch64: Use symbolic names for branches Richard Henderson
2014-03-24 15:31 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 09/26] tcg-aarch64: Create tcg_out_brcond Richard Henderson
2014-03-24 15:31 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 10/26] tcg-aarch64: Use CBZ and CBNZ Richard Henderson
2014-03-24 15:32 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 11/26] tcg-aarch64: Reuse FP and LR in translated code Richard Henderson
2014-03-28 9:48 ` Claudio Fontana
2014-03-28 13:23 ` Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 12/26] tcg-aarch64: Introduce tcg_out_insn_3314 Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 13/26] tcg-aarch64: Rearrange prologue insn order Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 14/26] tcg-aarch64: Implement tcg_register_jit Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 15/26] tcg-aarch64: Avoid add with zero in tlb load Richard Henderson
2014-03-26 9:36 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 16/26] tcg-aarch64: Use tcg_out_call for qemu_ld/st Richard Henderson
2014-03-26 9:37 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 17/26] tcg-aarch64: Use ADR to pass the return address to the ld/st helpers Richard Henderson
2014-03-26 9:38 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 18/26] tcg-aarch64: Use TCGMemOp in qemu_ld/st Richard Henderson
2014-03-26 9:39 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 19/26] tcg-aarch64: Implement TCG_TARGET_HAS_new_ldst Richard Henderson
2014-03-26 9:40 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 20/26] tcg-aarch64: Introduce tcg_out_insn_3507 Richard Henderson
2014-03-26 9:40 ` Claudio Fontana
2014-03-15 2:48 ` [Qemu-devel] [PATCH 21/26] tcg-aarch64: Merge aarch64_ldst_get_data/type into tcg_out_op Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 22/26] tcg-aarch64: Replace aarch64_ldst_op_data with TCGMemOp Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 23/26] tcg-aarch64: Replace aarch64_ldst_op_data with AArch64LdstType Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 24/26] tcg-aarch64: Prefer unsigned offsets before signed offsets for ldst Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 25/26] tcg-aarch64: Merge tcg_out_movr with tcg_out_mov Richard Henderson
2014-03-15 2:48 ` [Qemu-devel] [PATCH 26/26] tcg-aarch64: Support stores of zero Richard Henderson
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