+ /* This code tries to make movcal emulation sufficiently
+ accurate for Linux purposes. This instruction writes
+ memory, and prior to that, always allocates a cache line.
+ It is used in two contexts:
+ - in memcpy, where data is copied in blocks, the first write
+ of to a block uses movca.l for performance.
+ - in arch/sh/mm/cache-sh4.c, movcal.l + ocbi combination is used
+ to flush the cache. Here, the data written by movcal.l is never
+ written to memory, and the data written is just bogus.
+
+ To simulate this, we simulate movcal.l, we store the value to memory,
+ but we also remember the previous content. If we see ocbi, we check
+ if movcal.l for that address was done previously. If so, the write should
+ not have hit the memory, so we restore the previous content.
+ When we see an instruction that is neither movca.l
+ nor ocbi, the previous content is discarded.
+
+ To optimize, we only try to flush stores when we're at the start of
+ TB, or if we already saw movca.l in this TB and did not flush stores
+ yet. */
+ if (ctx->has_movcal)
+ {
+ int opcode = ctx->opcode & 0xf0ff;
+ if (opcode != 0x0093 /* ocbi */
+ && opcode != 0x00c3 /* movca.l */)
+ {
+ gen_helper_discard_movcal_backup ();
+ ctx->has_movcal = 0;
+ }
+ }
+