tcg/ppc: Split out tcg_out_bswap32

Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
qemu · Jun 29, 2021 · 8a611d8 · 8a611d8
1 parent 783d3ec
commit 8a611d8
Showing 1 changed file with 22 additions and 16 deletions.
diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
@@ -807,6 +807,27 @@ static void tcg_out_bswap16(TCGContext *s, TCGReg dst, TCGReg src)
     tcg_out_mov(s, TCG_TYPE_REG, dst, tmp);
 }
 
+static void tcg_out_bswap32(TCGContext *s, TCGReg dst, TCGReg src)
+{
+    TCGReg tmp = dst == src ? TCG_REG_R0 : dst;
+
+    /*
+     * Stolen from gcc's builtin_bswap32.
+     * In the following,
+     *   dep(a, b, m) -> (a & ~m) | (b & m)
+     *
+     * Begin with:                              src = xxxxabcd
+     */
+    /* tmp = rol32(src, 8) & 0xffffffff             = 0000bcda */
+    tcg_out_rlw(s, RLWINM, tmp, src, 8, 0, 31);
+    /* tmp = dep(tmp, rol32(src, 24), 0xff000000)   = 0000dcda */
+    tcg_out_rlw(s, RLWIMI, tmp, src, 24, 0, 7);
+    /* tmp = dep(tmp, rol32(src, 24), 0x0000ff00)   = 0000dcba */
+    tcg_out_rlw(s, RLWIMI, tmp, src, 24, 16, 23);
+
+    tcg_out_mov(s, TCG_TYPE_REG, dst, tmp);
+}
+
 /* Emit a move into ret of arg, if it can be done in one insn.  */
 static bool tcg_out_movi_one(TCGContext *s, TCGReg ret, tcg_target_long arg)
 {
@@ -2799,24 +2820,9 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc,
     case INDEX_op_bswap16_i64:
         tcg_out_bswap16(s, args[0], args[1]);
         break;
-
     case INDEX_op_bswap32_i32:
     case INDEX_op_bswap32_i64:
-        /* Stolen from gcc's builtin_bswap32 */
-        a1 = args[1];
-        a0 = args[0] == a1 ? TCG_REG_R0 : args[0];
-
-        /* a1 = args[1] # abcd */
-        /* a0 = rotate_left (a1, 8) # bcda */
-        tcg_out_rlw(s, RLWINM, a0, a1, 8, 0, 31);
-        /* a0 = (a0 & ~0xff000000) | ((a1 r<< 24) & 0xff000000) # dcda */
-        tcg_out_rlw(s, RLWIMI, a0, a1, 24, 0, 7);
-        /* a0 = (a0 & ~0x0000ff00) | ((a1 r<< 24) & 0x0000ff00) # dcba */
-        tcg_out_rlw(s, RLWIMI, a0, a1, 24, 16, 23);
-
-        if (a0 == TCG_REG_R0) {
-            tcg_out_mov(s, TCG_TYPE_REG, args[0], a0);
-        }
+        tcg_out_bswap32(s, args[0], args[1]);
         break;
 
     case INDEX_op_bswap64_i64: