Re: [PATCH 1/2] target/xtensa: Implement xtensa_isa_is_big_endian()

[Philippe Mathieu-Daudé]

Hi Max,

On 6/12/24 13:35, Max Filippov wrote:

On Thu, Dec 5, 2024 at 3:24 PM Philippe Mathieu-Daudé <phi...@linaro.org> wrote:

Xtensa internal fields are opaque, only accessible by
the Xtensa libisa. Implement xtensa_isa_is_big_endian()
to get vCPU endianness. This should be implemented in
libisa, not QEMU, but I couldn't figure out where to
contribute this.

This is a beautified version of what xtensa has in binutils, but
binutils is also
just another user of that internal Tensilica library. Perhaps I should make
an artificial "upstream" for this library just to track this kind of changes.
Let me look at it.

Could you add this method to the Tensilica library?

Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  include/hw/xtensa/xtensa-isa.h | 1 +
  target/xtensa/xtensa-isa.c     | 7 +++++++
  2 files changed, 8 insertions(+)

diff --git a/include/hw/xtensa/xtensa-isa.h b/include/hw/xtensa/xtensa-isa.h
index a289531bdc8..1cb8e6ccb66 100644
--- a/include/hw/xtensa/xtensa-isa.h
+++ b/include/hw/xtensa/xtensa-isa.h
@@ -829,6 +829,7 @@ const char *xtensa_funcUnit_name(xtensa_isa isa, 
xtensa_funcUnit fun);

  int xtensa_funcUnit_num_copies(xtensa_isa isa, xtensa_funcUnit fun);

+bool xtensa_isa_is_big_endian(xtensa_isa isa);

This file doesn't include stdbool.h and other boolean functions in it
(e.g. xtensa_opcode_is_branch()) return int. I'd suggest sticking with
that. With that change:

Acked-by: Max Filippov <jcmvb...@gmail.com>

  #ifdef __cplusplus
  }
diff --git a/target/xtensa/xtensa-isa.c b/target/xtensa/xtensa-isa.c
index 630b4f9da1b..36eb4bcf3d4 100644
--- a/target/xtensa/xtensa-isa.c
+++ b/target/xtensa/xtensa-isa.c
@@ -1741,3 +1741,10 @@ int xtensa_funcUnit_num_copies(xtensa_isa isa, 
xtensa_funcUnit fun)
      CHECK_FUNCUNIT(intisa, fun, XTENSA_UNDEFINED);
      return intisa->funcUnits[fun].num_copies;
  }
+
+bool xtensa_isa_is_big_endian(xtensa_isa isa)
+{
+    xtensa_isa_internal *intisa = (xtensa_isa_internal *)isa;
+
+    return intisa->is_big_endian;
+}