Paul Mundt lethal at linux-sh dot org writes:

We can't use trapa #0xff on sh2, the only permissible trapa ranges are
32 to 63. On SH-2, we use trapa32 to issue a break in the same way that
trapa #0xff is used on SH-3/4. This behavior is implementation specific,
but is what is used in sh-ipl+g, linux, eCos, uITRON, etc. so we follow
suit here.

libc/stdlib/abort.c

@@ -50,6 +50,8 @@ Cambridge, MA 02139, USA.  */
 #define ABORT_INSTRUCTION asm (".long 0")
 #elif defined(__SH5__)
 #define ABORT_INSTRUCTION asm ("movi 0x10, r9; shori 0xff, r9; trapa r9")
+#elif defined(__sh2__)
+#define ABORT_INSTRUCTION asm ("trapa #32")
 #elif defined(__sh__)
 #define ABORT_INSTRUCTION asm ("trapa #0xff")
 #else