Re: [Qemu-devel] [PATCH v16 22/23] target/rx: Collect all bytes during disassembly

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

On 5/31/19 3:43 PM, Richard Henderson wrote:
> Collected, to be used in the next patch.
> 
> Reviewed-by: Yoshinori Sato <ysato@users.sourceforge.jp>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  target/rx/disas.c | 62 ++++++++++++++++++++++++++++++++---------------
>  1 file changed, 42 insertions(+), 20 deletions(-)
> 
> diff --git a/target/rx/disas.c b/target/rx/disas.c
> index ebc1a44249..5a32a87534 100644
> --- a/target/rx/disas.c
> +++ b/target/rx/disas.c
> @@ -25,43 +25,59 @@ typedef struct DisasContext {
>      disassemble_info *dis;
>      uint32_t addr;
>      uint32_t pc;
> +    uint8_t len;
> +    uint8_t bytes[8];
>  } DisasContext;
>  
>  
>  static uint32_t decode_load_bytes(DisasContext *ctx, uint32_t insn,
> -                           int i, int n)
> +                                  int i, int n)
>  {
> -    bfd_byte buf;
> +    uint32_t addr = ctx->addr;
> +
> +    g_assert(ctx->len == i);
> +    g_assert(n <= ARRAY_SIZE(ctx->bytes));
> +
>      while (++i <= n) {
> -        ctx->dis->read_memory_func(ctx->addr++, &buf, 1, ctx->dis);
> -        insn |= buf << (32 - i * 8);
> +        ctx->dis->read_memory_func(addr++, &ctx->bytes[i - 1], 1, ctx->dis);
> +        insn |= ctx->bytes[i - 1] << (32 - i * 8);
>      }
> +    ctx->addr = addr;
> +    ctx->len = n;
> +
>      return insn;
>  }
>  
>  static int32_t li(DisasContext *ctx, int sz)
>  {
> -    int32_t addr;
> -    bfd_byte buf[4];
> -    addr = ctx->addr;
> +    uint32_t addr = ctx->addr;
> +    uintptr_t len = ctx->len;
>  
>      switch (sz) {
>      case 1:
> +        g_assert(len + 1 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 1;
> -        ctx->dis->read_memory_func(addr, buf, 1, ctx->dis);
> -        return (int8_t)buf[0];
> +        ctx->len += 1;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 1, ctx->dis);
> +        return (int8_t)ctx->bytes[len];
>      case 2:
> +        g_assert(len + 2 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 2;
> -        ctx->dis->read_memory_func(addr, buf, 2, ctx->dis);
> -        return ldsw_le_p(buf);
> +        ctx->len += 2;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 2, ctx->dis);
> +        return ldsw_le_p(ctx->bytes + len);
>      case 3:
> +        g_assert(len + 3 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 3;
> -        ctx->dis->read_memory_func(addr, buf, 3, ctx->dis);
> -        return (int8_t)buf[2] << 16 | lduw_le_p(buf);
> +        ctx->len += 3;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 3, ctx->dis);
> +        return (int8_t)ctx->bytes[len + 2] << 16 | lduw_le_p(ctx->bytes + len);
>      case 0:
> +        g_assert(len + 4 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 4;
> -        ctx->dis->read_memory_func(addr, buf, 4, ctx->dis);
> -        return ldl_le_p(buf);
> +        ctx->len += 4;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 4, ctx->dis);
> +        return ldl_le_p(ctx->bytes + len);
>      default:
>          g_assert_not_reached();
>      }
> @@ -110,7 +126,7 @@ static const char psw[] = {
>  static void rx_index_addr(DisasContext *ctx, char out[8], int ld, int mi)
>  {
>      uint32_t addr = ctx->addr;
> -    uint8_t buf[2];
> +    uintptr_t len = ctx->len;
>      uint16_t dsp;
>  
>      switch (ld) {
> @@ -119,14 +135,18 @@ static void rx_index_addr(DisasContext *ctx, char out[8], int ld, int mi)
>          out[0] = '\0';
>          return;
>      case 1:
> +        g_assert(len + 1 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 1;
> -        ctx->dis->read_memory_func(addr, buf, 1, ctx->dis);
> -        dsp = buf[0];
> +        ctx->len += 1;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 1, ctx->dis);
> +        dsp = ctx->bytes[len];
>          break;
>      case 2:
> +        g_assert(len + 2 <= ARRAY_SIZE(ctx->bytes));
>          ctx->addr += 2;
> -        ctx->dis->read_memory_func(addr, buf, 2, ctx->dis);
> -        dsp = lduw_le_p(buf);
> +        ctx->len += 2;
> +        ctx->dis->read_memory_func(addr, ctx->bytes + len, 2, ctx->dis);
> +        dsp = lduw_le_p(ctx->bytes + len);
>          break;
>      default:
>          g_assert_not_reached();
> @@ -1392,8 +1412,10 @@ int print_insn_rx(bfd_vma addr, disassemble_info *dis)
>      DisasContext ctx;
>      uint32_t insn;
>      int i;
> +
>      ctx.dis = dis;
>      ctx.pc = ctx.addr = addr;
> +    ctx.len = 0;
>  
>      insn = decode_load(&ctx);
>      if (!decode(&ctx, insn)) {
> 

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>