+void
+rs6000_expand_compare_and_swapqhi (rtx dst, rtx mem, rtx oldval, rtx newval)
+{
+ enum machine_mode mode = GET_MODE (mem);
+ rtx addrSI, align, wdst, shift, mask;
+ HOST_WIDE_INT shift_mask = mode == QImode ? 0x18 : 0x10;
+ HOST_WIDE_INT imask = GET_MODE_MASK (mode);
+
+ /* Shift amount for subword relative to aligned word. */
+ addrSI = force_reg (SImode, gen_lowpart_common (SImode, XEXP (mem, 0)));
+ shift = gen_reg_rtx (SImode);
+ emit_insn (gen_rlwinm (shift, addrSI, GEN_INT (3),
+ GEN_INT (shift_mask)));
+ emit_insn (gen_xorsi3 (shift, shift, GEN_INT (shift_mask)));
+
+ /* Shift and mask old value into position within word. */
+ oldval = convert_modes (SImode, mode, oldval, 1);
+ oldval = expand_binop (SImode, and_optab,
+ oldval, GEN_INT (imask), NULL_RTX,
+ 1, OPTAB_LIB_WIDEN);
+ emit_insn (gen_ashlsi3 (oldval, oldval, shift));
+
+ /* Shift and mask new value into position within word. */
+ newval = convert_modes (SImode, mode, newval, 1);
+ newval = expand_binop (SImode, and_optab,
+ newval, GEN_INT (imask), NULL_RTX,
+ 1, OPTAB_LIB_WIDEN);
+ emit_insn (gen_ashlsi3 (newval, newval, shift));
+
+ /* Mask for insertion. */
+ mask = gen_reg_rtx (SImode);
+ emit_move_insn (mask, GEN_INT (imask));
+ emit_insn (gen_ashlsi3 (mask, mask, shift));
+
+ /* Address of aligned word containing subword. */
+ align = expand_binop (Pmode, and_optab, XEXP (mem, 0), GEN_INT (-4),
+ NULL_RTX, 1, OPTAB_LIB_WIDEN);
+ mem = change_address (mem, SImode, align);
+ set_mem_align (mem, 32);
+ MEM_VOLATILE_P (mem) = 1;
+
+ wdst = gen_reg_rtx (SImode);
+ emit_insn (gen_sync_compare_and_swapqhi_internal (wdst, mask,
+ oldval, newval, mem));
+
+ emit_move_insn (dst, gen_lowpart (mode, wdst));
+}
+
+void
+rs6000_split_compare_and_swapqhi (rtx dest, rtx mask,
+ rtx oldval, rtx newval, rtx mem,
+ rtx scratch)
+{
+ rtx label1, label2, x, cond = gen_rtx_REG (CCmode, CR0_REGNO);
+
+ emit_insn (gen_memory_barrier ());
+ label1 = gen_rtx_LABEL_REF (VOIDmode, gen_label_rtx ());
+ label2 = gen_rtx_LABEL_REF (VOIDmode, gen_label_rtx ());
+ emit_label (XEXP (label1, 0));
+
+ emit_load_locked (SImode, scratch, mem);
+
+ /* Mask subword within loaded value for comparison with oldval.
+ Use UNSPEC_AND to avoid clobber.*/
+ emit_insn (gen_rtx_SET (SImode, dest,
+ gen_rtx_UNSPEC (SImode,
+ gen_rtvec (2, scratch, mask),
+ UNSPEC_AND)));
+
+ x = gen_rtx_COMPARE (CCmode, dest, oldval);
+ emit_insn (gen_rtx_SET (VOIDmode, cond, x));
+
+ x = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+ emit_unlikely_jump (x, label2);
+
+ /* Clear subword within loaded value for insertion of new value. */
+ emit_insn (gen_rtx_SET (SImode, scratch,
+ gen_rtx_AND (SImode,
+ gen_rtx_NOT (SImode, mask), scratch)));
+ emit_insn (gen_iorsi3 (scratch, scratch, newval));
+ emit_store_conditional (SImode, cond, mem, scratch);
+
+ x = gen_rtx_NE (VOIDmode, cond, const0_rtx);
+ emit_unlikely_jump (x, label1);
+
+ emit_insn (gen_isync ());
+ emit_label (XEXP (label2, 0));
+}
+
+