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

Message ID 20250417131004.47205-9-philmd@linaro.org
State New
Headers show
Series misc: Prefer evaluating TARGET_BIG_ENDIAN in C | expand

Commit Message

Philippe Mathieu-Daudé April 17, 2025, 1:10 p.m. UTC 
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 <philmd@linaro.org>
---
 include/gdbstub/helpers.h | 11 ++---------
 1 file changed, 2 insertions(+), 9 deletions(-)

Comments

Alex Bennée April 17, 2025, 4:18 p.m. UTC | #1 
Philippe Mathieu-Daudé <philmd@linaro.org> writes:

> 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 <philmd@linaro.org>

Acked-by: Alex Bennée <alex.bennee@linaro.org>
Richard Henderson April 18, 2025, 6:01 p.m. UTC | #2 
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 <philmd@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~
diff mbox series

Patch

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;
 }