From: Alistair Francis <alistair23@gmail.com> To: Richard Henderson <richard.henderson@linaro.org> Cc: Alistair Francis <Alistair.Francis@wdc.com>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>, qemu-riscv@nongnu.org Subject: Re: [Qemu-devel] [RFC v1 15/23] riscv: tcg-target: Add branch and jump instructions Date: Tue, 20 Nov 2018 15:49:29 -0800 [thread overview] Message-ID: <CAKmqyKP5cCRZujTm+OvoNZWNwPhJirPLA7PjurbovnN8RYCcgQ@mail.gmail.com> (raw) In-Reply-To: <23831afc-0ebf-5802-e8e2-6ce48dd340f9@linaro.org> On Fri, Nov 16, 2018 at 1:14 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > On 11/15/18 11:36 PM, Alistair Francis wrote: > > +static void tcg_out_brcond(TCGContext *s, TCGCond cond, TCGReg arg1, > > + TCGReg arg2, TCGLabel *l) > > +{ > > + RISCVInsn op = tcg_brcond_to_riscv[cond].op; > > + bool swap = tcg_brcond_to_riscv[cond].swap; > > + > > + tcg_out_opc_branch(s, op, swap ? arg2 : arg1, swap ? arg1 : arg2, 0); > > You might want to tcg_debug_assert(op != 0) here. > > > + if (l->has_value) { > > + reloc_sbimm12(s->code_ptr - 1, l->u.value_ptr); > > I'm concerned about the conditional branch range. +-4K isn't much to work > with. The minimum we have for other hosts is +-32K. > > We have two options: (1) greatly reduce the max size of the TB for this host; > (2) be prepared to emit a 2 insn sequence: conditional branch across > unconditional branch, with forward branches that turn out to be small patched > with a nop. > > FWIW, the first case would be done via modification of tcg_op_buf_full. You > might have to go as low as 500 opcodes, I'm not sure. How do we do option 2? > > > +static inline void tcg_out_goto(TCGContext *s, tcg_insn_unit *target) > > +{ > > + ptrdiff_t offset = tcg_pcrel_diff(s, target); > > + tcg_debug_assert(offset == sextract64(offset, 0, 26)); > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_ZERO, offset); > > +} > > + > > +static inline void tcg_out_goto_long(TCGContext *s, tcg_insn_unit *target) > > +{ > > + ptrdiff_t offset = tcg_pcrel_diff(s, target); > > + > > + if (offset == sextract64(offset, 0, 26)) { > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_ZERO, offset); > > + } else { > > + tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP0, (intptr_t)target); > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_TMP0, 0); > > + } > > +} > > How are these to be used? I guess I'll find out... It's called on a exit TB op. I'm not sure if that's correct though. Alistair > > > +static void tcg_out_call_int(TCGContext *s, tcg_insn_unit *arg, bool tail) > > +{ > > + TCGReg link = tail ? TCG_REG_ZERO : TCG_REG_RA; > > + ptrdiff_t offset = tcg_pcrel_diff(s, arg); > > + if (offset == sextract32(offset, 1, 20) << 1) { > > sextract64. > > > + /* short jump: -2097150 to 2097152 */ > > + tcg_out_opc_jump(s, OPC_JAL, link, offset); > > + } else if (TCG_TARGET_REG_BITS == 32 || > > + offset == sextract32(offset, 1, 31) << 1) { > > sextract64. > > > + /* long jump: -2147483646 to 2147483648 */ > > + tcg_out_opc_upper(s, OPC_AUIPC, TCG_REG_TMP0, 0); > > + tcg_out_opc_imm(s, OPC_JALR, link, TCG_REG_TMP0, 0); > > + reloc_call(s->code_ptr - 2, arg); > > + } else if (TCG_TARGET_REG_BITS == 64) { > > + /* far jump: 64-bit */ > > + tcg_target_long imm = sextract32((tcg_target_long)arg, 0, 12); > > + tcg_target_long base = (tcg_target_long)arg - imm; > > + tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP0, base); > > + tcg_out_opc_imm(s, OPC_JALR, link, TCG_REG_TMP0, imm); > > > r~
WARNING: multiple messages have this Message-ID (diff)
From: Alistair Francis <alistair23@gmail.com> To: Richard Henderson <richard.henderson@linaro.org> Cc: Alistair Francis <Alistair.Francis@wdc.com>, "qemu-devel@nongnu.org Developers" <qemu-devel@nongnu.org>, qemu-riscv@nongnu.org Subject: Re: [Qemu-riscv] [Qemu-devel] [RFC v1 15/23] riscv: tcg-target: Add branch and jump instructions Date: Tue, 20 Nov 2018 15:49:29 -0800 [thread overview] Message-ID: <CAKmqyKP5cCRZujTm+OvoNZWNwPhJirPLA7PjurbovnN8RYCcgQ@mail.gmail.com> (raw) In-Reply-To: <23831afc-0ebf-5802-e8e2-6ce48dd340f9@linaro.org> On Fri, Nov 16, 2018 at 1:14 AM Richard Henderson <richard.henderson@linaro.org> wrote: > > On 11/15/18 11:36 PM, Alistair Francis wrote: > > +static void tcg_out_brcond(TCGContext *s, TCGCond cond, TCGReg arg1, > > + TCGReg arg2, TCGLabel *l) > > +{ > > + RISCVInsn op = tcg_brcond_to_riscv[cond].op; > > + bool swap = tcg_brcond_to_riscv[cond].swap; > > + > > + tcg_out_opc_branch(s, op, swap ? arg2 : arg1, swap ? arg1 : arg2, 0); > > You might want to tcg_debug_assert(op != 0) here. > > > + if (l->has_value) { > > + reloc_sbimm12(s->code_ptr - 1, l->u.value_ptr); > > I'm concerned about the conditional branch range. +-4K isn't much to work > with. The minimum we have for other hosts is +-32K. > > We have two options: (1) greatly reduce the max size of the TB for this host; > (2) be prepared to emit a 2 insn sequence: conditional branch across > unconditional branch, with forward branches that turn out to be small patched > with a nop. > > FWIW, the first case would be done via modification of tcg_op_buf_full. You > might have to go as low as 500 opcodes, I'm not sure. How do we do option 2? > > > +static inline void tcg_out_goto(TCGContext *s, tcg_insn_unit *target) > > +{ > > + ptrdiff_t offset = tcg_pcrel_diff(s, target); > > + tcg_debug_assert(offset == sextract64(offset, 0, 26)); > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_ZERO, offset); > > +} > > + > > +static inline void tcg_out_goto_long(TCGContext *s, tcg_insn_unit *target) > > +{ > > + ptrdiff_t offset = tcg_pcrel_diff(s, target); > > + > > + if (offset == sextract64(offset, 0, 26)) { > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_ZERO, offset); > > + } else { > > + tcg_out_movi(s, TCG_TYPE_I64, TCG_REG_TMP0, (intptr_t)target); > > + tcg_out_opc_jump(s, OPC_JAL, TCG_REG_TMP0, 0); > > + } > > +} > > How are these to be used? I guess I'll find out... It's called on a exit TB op. I'm not sure if that's correct though. Alistair > > > +static void tcg_out_call_int(TCGContext *s, tcg_insn_unit *arg, bool tail) > > +{ > > + TCGReg link = tail ? TCG_REG_ZERO : TCG_REG_RA; > > + ptrdiff_t offset = tcg_pcrel_diff(s, arg); > > + if (offset == sextract32(offset, 1, 20) << 1) { > > sextract64. > > > + /* short jump: -2097150 to 2097152 */ > > + tcg_out_opc_jump(s, OPC_JAL, link, offset); > > + } else if (TCG_TARGET_REG_BITS == 32 || > > + offset == sextract32(offset, 1, 31) << 1) { > > sextract64. > > > + /* long jump: -2147483646 to 2147483648 */ > > + tcg_out_opc_upper(s, OPC_AUIPC, TCG_REG_TMP0, 0); > > + tcg_out_opc_imm(s, OPC_JALR, link, TCG_REG_TMP0, 0); > > + reloc_call(s->code_ptr - 2, arg); > > + } else if (TCG_TARGET_REG_BITS == 64) { > > + /* far jump: 64-bit */ > > + tcg_target_long imm = sextract32((tcg_target_long)arg, 0, 12); > > + tcg_target_long base = (tcg_target_long)arg - imm; > > + tcg_out_movi(s, TCG_TYPE_PTR, TCG_REG_TMP0, base); > > + tcg_out_opc_imm(s, OPC_JALR, link, TCG_REG_TMP0, imm); > > > r~
next prev parent reply other threads:[~2018-11-20 23:50 UTC|newest] Thread overview: 130+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-11-15 22:33 [Qemu-devel] [RFC v1 00/23] Add RISC-V TCG backend support Alistair Francis 2018-11-15 22:33 ` [Qemu-riscv] " Alistair Francis 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 01/23] elf.h: Add the RISCV ELF magic numbers Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:46 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:46 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 02/23] linux-user: Add host dependency for RISC-V 32-bit Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:46 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:46 ` [Qemu-riscv] " Richard Henderson 2018-11-16 7:47 ` Richard Henderson 2018-11-16 7:47 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 03/23] linux-user: Add host dependency for RISC-V 64-bit Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:57 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:57 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 04/23] exec: Add RISC-V GCC poison macro Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:47 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:47 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 05/23] riscv: Add the tcg-target header file Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:57 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:57 ` [Qemu-riscv] " Richard Henderson 2018-11-16 17:20 ` Richard Henderson 2018-11-16 17:20 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 06/23] riscv: Add the tcg target registers Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:58 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:58 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:34 ` [Qemu-devel] [RFC v1 07/23] riscv: tcg-target: Regiser the JIT Alistair Francis 2018-11-15 22:34 ` [Qemu-riscv] " Alistair Francis 2018-11-16 7:59 ` [Qemu-devel] " Richard Henderson 2018-11-16 7:59 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 08/23] riscv: tcg-target: Add support for the constraints Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:13 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:13 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 09/23] riscv: tcg-target: Add the immediate encoders Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:26 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:26 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 10/23] riscv: tcg-target: Add the instruction emitters Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:27 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:27 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 11/23] riscv: tcg-target: Add the relocation functions Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:33 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:33 ` [Qemu-riscv] " Richard Henderson 2018-11-21 1:15 ` Alistair Francis 2018-11-21 1:15 ` [Qemu-riscv] " Alistair Francis 2018-11-21 7:25 ` Richard Henderson 2018-11-21 7:25 ` [Qemu-riscv] " Richard Henderson 2018-11-21 15:53 ` Palmer Dabbelt 2018-11-21 15:53 ` [Qemu-riscv] " Palmer Dabbelt 2018-11-21 17:01 ` Richard Henderson 2018-11-21 17:01 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 12/23] riscv: tcg-target: Add the mov and movi instruction Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:55 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:55 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:35 ` [Qemu-devel] [RFC v1 13/23] riscv: tcg-target: Add the extract instructions Alistair Francis 2018-11-15 22:35 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:56 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:56 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 14/23] riscv: tcg-target: Add the out load and store instructions Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 8:59 ` [Qemu-devel] " Richard Henderson 2018-11-16 8:59 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 15/23] riscv: tcg-target: Add branch and jump instructions Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 9:14 ` [Qemu-devel] " Richard Henderson 2018-11-16 9:14 ` [Qemu-riscv] " Richard Henderson 2018-11-20 23:49 ` Alistair Francis [this message] 2018-11-20 23:49 ` Alistair Francis 2018-11-21 7:40 ` Richard Henderson 2018-11-21 7:40 ` [Qemu-riscv] " Richard Henderson 2018-11-26 22:58 ` Alistair Francis 2018-11-26 22:58 ` [Qemu-riscv] " Alistair Francis 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 16/23] riscv: tcg-target: Add slowpath load and store instructions Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 9:24 ` [Qemu-devel] " Richard Henderson 2018-11-16 9:24 ` [Qemu-riscv] " Richard Henderson 2018-11-21 0:18 ` Alistair Francis 2018-11-21 0:18 ` [Qemu-riscv] " Alistair Francis 2018-11-21 7:43 ` Richard Henderson 2018-11-21 7:43 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 17/23] riscv: tcg-target: Add direct " Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:10 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:10 ` [Qemu-riscv] " Richard Henderson 2018-11-19 23:06 ` Alistair Francis 2018-11-19 23:06 ` [Qemu-riscv] " Alistair Francis 2018-11-20 6:57 ` Richard Henderson 2018-11-20 6:57 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 18/23] riscv: tcg-target: Add the out op decoder Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:22 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:22 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 19/23] riscv: tcg-target: Add the prologue generation Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:25 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:25 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:36 ` [Qemu-devel] [RFC v1 20/23] riscv: tcg-target: Add the target init code Alistair Francis 2018-11-15 22:36 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:26 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:26 ` [Qemu-riscv] " Richard Henderson 2018-11-19 23:04 ` Alistair Francis 2018-11-19 23:04 ` [Qemu-riscv] " Alistair Francis 2018-11-20 6:55 ` Richard Henderson 2018-11-20 6:55 ` [Qemu-riscv] " Richard Henderson 2018-11-20 23:22 ` Alistair Francis 2018-11-20 23:22 ` [Qemu-riscv] " Alistair Francis 2018-11-15 22:37 ` [Qemu-devel] [RFC v1 21/23] tcg: Add RISC-V cpu signal handler Alistair Francis 2018-11-15 22:37 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:27 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:27 ` [Qemu-riscv] " Richard Henderson 2018-11-16 17:29 ` Richard Henderson 2018-11-16 17:29 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:37 ` [Qemu-devel] [RFC v1 22/23] dias: Add RISC-V support Alistair Francis 2018-11-15 22:37 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:29 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:29 ` [Qemu-riscv] " Richard Henderson 2018-11-15 22:37 ` [Qemu-devel] [RFC v1 23/23] configure: Add support for building RISC-V host Alistair Francis 2018-11-15 22:37 ` [Qemu-riscv] " Alistair Francis 2018-11-16 17:30 ` [Qemu-devel] " Richard Henderson 2018-11-16 17:30 ` [Qemu-riscv] " Richard Henderson 2018-11-16 8:31 ` [Qemu-devel] [RFC v1 00/23] Add RISC-V TCG backend support no-reply 2018-11-16 8:31 ` [Qemu-riscv] " no-reply
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