gdbstub/helpers: Replace TARGET_BIG_ENDIAN -> target_big_endian()

Check endianness at runtime to remove the target-specific
TARGET_BIG_ENDIAN definition. Use cpu_to_[be,le]XX() from
"qemu/bswap.h" instead of tswapXX() from "exec/tswap.h".

Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20250708215320.70426-7-philmd@linaro.org>
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

include/gdbstub/helpers.h

@@ -16,7 +16,8 @@
 #error "gdbstub helpers should only be included by target specific code"
 #endif
 
-#include "exec/tswap.h"
+#include "qemu/bswap.h"
+#include "qemu/target-info.h"
 #include "cpu-param.h"
 
 /*
@@ -33,40 +34,49 @@ static inline int gdb_get_reg8(GByteArray *buf, uint8_t val)
 
 static inline int gdb_get_reg16(GByteArray *buf, uint16_t val)
 {
-    uint16_t to_word = tswap16(val);
-    g_byte_array_append(buf, (uint8_t *) &to_word, 2);
+    if (target_big_endian()) {
+        cpu_to_be16s(&val);
+    } else {
+        cpu_to_le16s(&val);
+    }
+    g_byte_array_append(buf, (uint8_t *) &val, 2);
     return 2;
 }
 
 static inline int gdb_get_reg32(GByteArray *buf, uint32_t val)
 {
-    uint32_t to_long = tswap32(val);
-    g_byte_array_append(buf, (uint8_t *) &to_long, 4);
+    if (target_big_endian()) {
+        cpu_to_be32s(&val);
+    } else {
+        cpu_to_le32s(&val);
+    }
+    g_byte_array_append(buf, (uint8_t *) &val, 4);
     return 4;
 }
 
 static inline int gdb_get_reg64(GByteArray *buf, uint64_t val)
 {
-    uint64_t to_quad = tswap64(val);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
+    if (target_big_endian()) {
+        cpu_to_be64s(&val);
+    } else {
+        cpu_to_le64s(&val);
+    }
+    g_byte_array_append(buf, (uint8_t *) &val, 8);
     return 8;
 }
 
 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);
-    g_byte_array_append(buf, (uint8_t *) &to_quad, 8);
-    to_quad = tswap64(val_lo);
-    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
+    uint64_t tmp[2];
+    if (target_big_endian()) {
+        tmp[0] = cpu_to_be64(val_hi);
+        tmp[1] = cpu_to_be64(val_lo);
+    } else {
+        tmp[0] = cpu_to_le64(val_lo);
+        tmp[1] = cpu_to_le64(val_hi);
+    }
+    g_byte_array_append(buf, (uint8_t *)&tmp, 16);
     return 16;
 }