Re: [PATCH 8/8] gdbstub/helpers: Evaluate TARGET_BIG_ENDIAN at compile time

[Richard Henderson]

On 4/17/25 06:10, Philippe Mathieu-Daudé wrote:

Rather than evaluating TARGET_BIG_ENDIAN at preprocessing
time via #ifdef'ry, do it in C at compile time

Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  include/gdbstub/helpers.h | 11 ++---------
  1 file changed, 2 insertions(+), 9 deletions(-)

diff --git a/include/gdbstub/helpers.h b/include/gdbstub/helpers.h
index 6f7cc48adcb..c33d5dfca3e 100644
--- a/include/gdbstub/helpers.h
+++ b/include/gdbstub/helpers.h
@@ -56,17 +56,10 @@ static inline int gdb_get_reg128(GByteArray *buf, uint64_t 
val_hi,
                                   uint64_t val_lo)
  {
      uint64_t to_quad;
-#if TARGET_BIG_ENDIAN
-    to_quad = tswap64(val_hi);
+    to_quad = tswap64(TARGET_BIG_ENDIAN ? val_hi : val_lo);
      g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    to_quad = tswap64(val_lo);
+    to_quad = tswap64(TARGET_BIG_ENDIAN ? val_lo : val_hi);
      g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-#else
-    to_quad = tswap64(val_lo);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    to_quad = tswap64(val_hi);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-#endif
      return 16;
  }

I'm not keen on using both TARGET_BIG_ENDIAN and tswap.
I think this ought to be

    uint64_t v0, v1;

    if (TARGET_BIG_ENDIAN) {
        v0 = cpu_to_be64(val_hi);
        v1 = cpu_to_be64(val_lo);
    } else {
        v0 = cpu_to_le64(val_lo);
        v1 = cpu_to_le64(val_hi);
    }
    g_byte_array_append(buf, (uint8_t *)&v0, 8);
    g_byte_array_append(buf, (uint8_t *)&v1, 8);


r~