Re: [PATCH v37 02/17] target/avr: Add instruction helpers

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 11/27/19 6:52 PM, Michael Rolnik wrote:
> Stubs for unimplemented instructions and helpers for instructions that need to interact with QEMU.
> SPM and WDR are unimplemented because they require emulation of complex peripherals.
> The implementation of SLEEP is very limited due to the lack of peripherals to generate wake interrupts.
> Memory access instructions are implemented here because some address ranges actually refer to CPU registers.
> 
> Signed-off-by: Michael Rolnik <mrolnik@gmail.com>
> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>   target/avr/helper.h |  29 ++++
>   target/avr/helper.c | 354 ++++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 383 insertions(+)
>   create mode 100644 target/avr/helper.h
>   create mode 100644 target/avr/helper.c
> 
> diff --git a/target/avr/helper.h b/target/avr/helper.h
> new file mode 100644
> index 0000000000..bf087504a8
> --- /dev/null
> +++ b/target/avr/helper.h
> @@ -0,0 +1,29 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +DEF_HELPER_1(wdr, void, env)
> +DEF_HELPER_1(debug, void, env)
> +DEF_HELPER_1(break, void, env)
> +DEF_HELPER_1(sleep, void, env)
> +DEF_HELPER_1(unsupported, void, env)
> +DEF_HELPER_3(outb, void, env, i32, i32)
> +DEF_HELPER_2(inb, tl, env, i32)
> +DEF_HELPER_3(fullwr, void, env, i32, i32)
> +DEF_HELPER_2(fullrd, tl, env, i32)
> diff --git a/target/avr/helper.c b/target/avr/helper.c
> new file mode 100644
> index 0000000000..f1939bd5a7
> --- /dev/null
> +++ b/target/avr/helper.c
> @@ -0,0 +1,354 @@
> +/*
> + * QEMU AVR CPU
> + *
> + * Copyright (c) 2019 Michael Rolnik
> + *
> + * This library is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This library is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, see
> + * <http://www.gnu.org/licenses/lgpl-2.1.html>
> + */
> +
> +#include "qemu/osdep.h"
> +
> +#include "cpu.h"
> +#include "hw/irq.h"

Nitpicking again, the previous include doesn't seem used.

> +#include "hw/sysbus.h"
> +#include "sysemu/sysemu.h"
> +#include "exec/exec-all.h"
> +#include "exec/cpu_ldst.h"
> +#include "exec/helper-proto.h"
> +#include "exec/ioport.h"
> +#include "qemu/host-utils.h"
> +#include "qemu/error-report.h"
> +
> +bool avr_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
> +{
> +    bool ret = false;
> +    CPUClass *cc = CPU_GET_CLASS(cs);
> +    AVRCPU *cpu = AVR_CPU(cs);
> +    CPUAVRState *env = &cpu->env;
> +
> +    if (interrupt_request & CPU_INTERRUPT_RESET) {
> +        if (cpu_interrupts_enabled(env)) {
> +            cs->exception_index = EXCP_RESET;
> +            cc->do_interrupt(cs);
> +
> +            cs->interrupt_request &= ~CPU_INTERRUPT_RESET;
> +
> +            ret = true;
> +        }
> +    }
> +    if (interrupt_request & CPU_INTERRUPT_HARD) {
> +        if (cpu_interrupts_enabled(env) && env->intsrc != 0) {
> +            int index = ctz32(env->intsrc);
> +            cs->exception_index = EXCP_INT(index);
> +            cc->do_interrupt(cs);
> +
> +            env->intsrc &= env->intsrc - 1; /* clear the interrupt */
> +            cs->interrupt_request &= ~CPU_INTERRUPT_HARD;
> +
> +            ret = true;
> +        }
> +    }
> +    return ret;
> +}
> +
> +void avr_cpu_do_interrupt(CPUState *cs)
> +{
> +    AVRCPU *cpu = AVR_CPU(cs);
> +    CPUAVRState *env = &cpu->env;
> +
> +    uint32_t ret = env->pc_w;
> +    int vector = 0;
> +    int size = avr_feature(env, AVR_FEATURE_JMP_CALL) ? 2 : 1;
> +    int base = 0;
> +
> +    if (cs->exception_index == EXCP_RESET) {
> +        vector = 0;
> +    } else if (env->intsrc != 0) {
> +        vector = ctz32(env->intsrc) + 1;
> +    }
> +
> +    if (avr_feature(env, AVR_FEATURE_3_BYTE_PC)) {
> +        cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
> +        cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
> +        cpu_stb_data(env, env->sp--, (ret & 0xff0000) >> 16);
> +    } else if (avr_feature(env, AVR_FEATURE_2_BYTE_PC)) {
> +        cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
> +        cpu_stb_data(env, env->sp--, (ret & 0x00ff00) >> 8);
> +    } else {
> +        cpu_stb_data(env, env->sp--, (ret & 0x0000ff));
> +    }
> +
> +    env->pc_w = base + vector * size;
> +    env->sregI = 0; /* clear Global Interrupt Flag */
> +
> +    cs->exception_index = -1;
> +}
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