From: Richard Henderson <richard.henderson@linaro.org>
To: WANG Xuerui <git@xen0n.name>, qemu-devel@nongnu.org
Subject: Re: [PATCH v2 09/30] tcg/loongarch64: Implement tcg_out_mov and tcg_out_movi
Date: Tue, 21 Sep 2021 21:25:10 -0700 [thread overview]
Message-ID: <0717a7de-7c41-990d-ec7a-51b44f49724e@linaro.org> (raw)
In-Reply-To: <20210921201915.601245-10-git@xen0n.name>
On 9/21/21 1:18 PM, WANG Xuerui wrote:
> + /* Test for PC-relative values that can be loaded faster. */
> + intptr_t pc_offset = val - (uintptr_t)s->code_ptr;
This isn't quite right for split r^x code buffer.
You should have seen this with --enable-debug-tcg...
You need pc_offset = tcg_pcrel_diff(s, (void *)val).
> + if (pc_offset == (int32_t)pc_offset) {
> + tcg_target_long lo = sextreg(pc_offset, 0, 12);
> + tcg_target_long hi = pc_offset - lo;
> + tcg_out_opc_pcaddu12i(s, rd, hi >> 12);
And... this doesn't quite work, right at the edges. If lo is negative, hi can overflow
out of range. There are a number of ways to fix this. One is to extract the pieces and
re-assemble to see if it matches. Another is to rearrange the arithmetic just a little
and use PCALAU12I.
> + tcg_target_long upper = (val >> 12) & 0xfffff;
> + tcg_target_long higher = (val >> 32) & 0xfffff;
Better to use extract64(val, 12, 20) and extract64(val, 32, 30).
r~
next prev parent reply other threads:[~2021-09-22 4:26 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-21 20:18 [PATCH v2 00/30] LoongArch64 port of QEMU TCG WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 01/30] elf: Add machine type value for LoongArch WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 02/30] MAINTAINERS: Add tcg/loongarch64 entry with myself as maintainer WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 03/30] tcg/loongarch64: Add the tcg-target.h file WANG Xuerui
2021-09-22 3:55 ` Richard Henderson
2021-09-22 4:33 ` WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 04/30] tcg/loongarch64: Add generated instruction opcodes and encoding helpers WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 05/30] tcg/loongarch64: Add register names, allocation order and input/output sets WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 06/30] tcg/loongarch64: Define the operand constraints WANG Xuerui
2021-09-22 3:59 ` Richard Henderson
2021-09-21 20:18 ` [PATCH v2 07/30] tcg/loongarch64: Implement necessary relocation operations WANG Xuerui
2021-09-22 4:02 ` Richard Henderson
2021-09-21 20:18 ` [PATCH v2 08/30] tcg/loongarch64: Implement the memory barrier op WANG Xuerui
2021-09-22 4:03 ` Richard Henderson
2021-09-21 20:18 ` [PATCH v2 09/30] tcg/loongarch64: Implement tcg_out_mov and tcg_out_movi WANG Xuerui
2021-09-22 4:25 ` Richard Henderson [this message]
2021-09-22 15:16 ` WANG Xuerui
2021-09-22 15:17 ` Richard Henderson
2021-09-22 17:22 ` WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 10/30] tcg/loongarch64: Implement goto_ptr WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 11/30] tcg/loongarch64: Implement sign-/zero-extension ops WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 12/30] tcg/loongarch64: Implement not/and/or/xor/nor/andc/orc/eqv ops WANG Xuerui
2021-09-22 4:35 ` Richard Henderson
2021-09-22 17:23 ` WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 13/30] tcg/loongarch64: Implement deposit/extract ops WANG Xuerui
2021-09-21 20:18 ` [PATCH v2 14/30] tcg/loongarch64: Implement bswap32_i32/bswap32_i64/bswap64_i64 WANG Xuerui
2021-09-22 14:54 ` Richard Henderson
2021-09-22 17:24 ` WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 15/30] tcg/loongarch64: Implement clz/ctz ops WANG Xuerui
2021-09-22 14:57 ` Richard Henderson
2021-09-21 20:19 ` [PATCH v2 16/30] tcg/loongarch64: Implement shl/shr/sar/rotl/rotr ops WANG Xuerui
2021-09-22 14:59 ` Richard Henderson
2021-09-21 20:19 ` [PATCH v2 17/30] tcg/loongarch64: Implement add/sub ops WANG Xuerui
2021-09-22 15:01 ` Richard Henderson
2021-09-21 20:19 ` [PATCH v2 18/30] tcg/loongarch64: Implement mul/mulsh/muluh/div/divu/rem/remu ops WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 19/30] tcg/loongarch64: Implement br/brcond ops WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 20/30] tcg/loongarch64: Implement setcond ops WANG Xuerui
2021-09-22 15:13 ` Richard Henderson
2021-09-22 17:26 ` WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 21/30] tcg/loongarch64: Implement tcg_out_call WANG Xuerui
2021-09-22 15:16 ` Richard Henderson
2021-09-21 20:19 ` [PATCH v2 22/30] tcg/loongarch64: Implement simple load/store ops WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 23/30] tcg/loongarch64: Add softmmu load/store helpers, implement qemu_ld/qemu_st ops WANG Xuerui
2021-09-22 16:29 ` Richard Henderson
2021-09-22 17:32 ` WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 24/30] tcg/loongarch64: Implement tcg_target_qemu_prologue WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 25/30] tcg/loongarch64: Implement exit_tb/goto_tb WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 26/30] tcg/loongarch64: Implement tcg_target_init WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 27/30] tcg/loongarch64: Register the JIT WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 28/30] linux-user: Add safe syscall handling for loongarch64 hosts WANG Xuerui
2021-09-22 16:39 ` Richard Henderson
2021-09-21 20:19 ` [PATCH v2 29/30] accel/tcg/user-exec: Implement CPU-specific signal handler " WANG Xuerui
2021-09-22 16:51 ` Richard Henderson
2021-09-22 17:35 ` WANG Xuerui
2021-09-21 20:19 ` [PATCH v2 30/30] configure, meson.build: Mark support " WANG Xuerui
2021-09-22 16:53 ` Richard Henderson
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