Re: [PATCH v5 1/6] target/arm/emulate: add ISV=0 emulation library with load/store immediate

[Richard Henderson <richard.henderson@linaro.org>]

On 3/18/26 03:47, Lucas Amaral wrote:
> +/* Memory access wrappers */
> +
> +static int mem_read(DisasContext *ctx, uint64_t va, void *buf, int size)
> +{
> +    if (((va & ~TARGET_PAGE_MASK) + size) > TARGET_PAGE_SIZE) {
> +        ctx->result = ARM_EMUL_ERR_MEM;
> +        return -1;
> +    }
> +    int ret = cpu_memory_rw_debug(ctx->cpu, va, buf, size, false);
> +    if (ret != 0) {
> +        ctx->result = ARM_EMUL_ERR_MEM;
> +    }
> +    return ret;
> +}

This is not implementing access for a debugger, but emulating an insn.
Thus *_debug is the wrong interface to use.

There is no direct interface for you to use here, because the ones we have at present will 
raise an exception and jump back to an emulation loop that doesn't exist here.  You'd need 
to translate the virtual address manually, recognize any exception raised, perform the 
access to the physical address, and recognize any hw exception raised.

> +/* Sign/zero extension helpers */
> +
> +static uint64_t sign_extend(uint64_t val, int from_bits)
> +{
> +    int shift = 64 - from_bits;
> +    return (int64_t)(val << shift) >> shift;
> +}

This is sextract64.

> +/* PRFM, DC cache maintenance -- treated as NOP */
> +static bool trans_NOP(DisasContext *ctx, arg_NOP *a)
> +{
> +    (void)ctx;
> +    (void)a;
> +    return true;
> +}

You don't need the (void) expressions.


r~