[Qemu-devel] [6205] CRIS: Use a helper for lz.

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

Revision: 6205
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=6205
Author:   edgar_igl
Date:     2009-01-07 13:19:21 +0000 (Wed, 07 Jan 2009)

Log Message:
-----------
CRIS: Use a helper for lz.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

Modified Paths:
--------------
    trunk/target-cris/helper.h
    trunk/target-cris/op_helper.c
    trunk/target-cris/translate.c

Modified: trunk/target-cris/helper.h
===================================================================
--- trunk/target-cris/helper.h	2009-01-07 13:15:29 UTC (rev 6204)
+++ trunk/target-cris/helper.h	2009-01-07 13:19:21 UTC (rev 6205)
@@ -10,6 +10,7 @@
 DEF_HELPER_2(movl_sreg_reg, void, i32, i32)
 DEF_HELPER_2(movl_reg_sreg, void, i32, i32)
 
+DEF_HELPER_FLAGS_1(lz, TCG_CALL_PURE, i32, i32);
 DEF_HELPER_FLAGS_3(btst, TCG_CALL_PURE, i32, i32, i32, i32);
 
 DEF_HELPER_0(evaluate_flags_muls, void)

Modified: trunk/target-cris/op_helper.c
===================================================================
--- trunk/target-cris/op_helper.c	2009-01-07 13:15:29 UTC (rev 6204)
+++ trunk/target-cris/op_helper.c	2009-01-07 13:19:21 UTC (rev 6205)
@@ -23,6 +23,7 @@
 #include "exec.h"
 #include "mmu.h"
 #include "helper.h"
+#include "host-utils.h"
 
 #define D(x)
 
@@ -243,6 +244,11 @@
     env->pregs[PR_CCS] |= M_FLAG;
 }
 
+uint32_t helper_lz(uint32_t t0)
+{
+	return clz32(t0);
+}
+
 uint32_t helper_btst(uint32_t t0, uint32_t t1, uint32_t ccs)
 {
 	/* FIXME: clean this up.  */

Modified: trunk/target-cris/translate.c
===================================================================
--- trunk/target-cris/translate.c	2009-01-07 13:15:29 UTC (rev 6204)
+++ trunk/target-cris/translate.c	2009-01-07 13:19:21 UTC (rev 6205)
@@ -320,74 +320,6 @@
 	tcg_temp_free_i64(t1);
 }
 
-/* 32bit branch-free binary search for counting leading zeros.  */
-static void t_gen_lz_i32(TCGv d, TCGv x)
-{
-	TCGv_i32 y, m, n;
-
-	y = tcg_temp_new_i32();
-	m = tcg_temp_new_i32();
-	n = tcg_temp_new_i32();
-
-	/* y = -(x >> 16)  */
-	tcg_gen_shri_i32(y, x, 16);
-	tcg_gen_neg_i32(y, y);
-
-	/* m = (y >> 16) & 16  */
-	tcg_gen_sari_i32(m, y, 16);
-	tcg_gen_andi_i32(m, m, 16);
-
-	/* n = 16 - m  */
-	tcg_gen_sub_i32(n, tcg_const_i32(16), m);
-	/* x = x >> m  */
-	tcg_gen_shr_i32(x, x, m);
-
-	/* y = x - 0x100  */
-	tcg_gen_subi_i32(y, x, 0x100);
-	/* m = (y >> 16) & 8  */
-	tcg_gen_sari_i32(m, y, 16);
-	tcg_gen_andi_i32(m, m, 8);
-	/* n = n + m  */
-	tcg_gen_add_i32(n, n, m);
-	/* x = x << m  */
-	tcg_gen_shl_i32(x, x, m);
-
-	/* y = x - 0x1000  */
-	tcg_gen_subi_i32(y, x, 0x1000);
-	/* m = (y >> 16) & 4  */
-	tcg_gen_sari_i32(m, y, 16);
-	tcg_gen_andi_i32(m, m, 4);
-	/* n = n + m  */
-	tcg_gen_add_i32(n, n, m);
-	/* x = x << m  */
-	tcg_gen_shl_i32(x, x, m);
-
-	/* y = x - 0x4000  */
-	tcg_gen_subi_i32(y, x, 0x4000);
-	/* m = (y >> 16) & 2  */
-	tcg_gen_sari_i32(m, y, 16);
-	tcg_gen_andi_i32(m, m, 2);
-	/* n = n + m  */
-	tcg_gen_add_i32(n, n, m);
-	/* x = x << m  */
-	tcg_gen_shl_i32(x, x, m);
-
-	/* y = x >> 14  */
-	tcg_gen_shri_i32(y, x, 14);
-	/* m = y & ~(y >> 1)  */
-	tcg_gen_sari_i32(m, y, 1);
-	tcg_gen_not_i32(m, m);
-	tcg_gen_and_i32(m, m, y);
-
-	/* d = n + 2 - m  */
-	tcg_gen_addi_i32(d, n, 2);
-	tcg_gen_sub_i32(d, d, m);
-
-	tcg_temp_free(y);
-	tcg_temp_free(m);
-	tcg_temp_free(n);
-}
-
 static void t_gen_cris_dstep(TCGv d, TCGv a, TCGv b)
 {
 	int l1;
@@ -825,7 +757,7 @@
 			t_gen_subx_carry(dc, dst);
 			break;
 		case CC_OP_LZ:
-			t_gen_lz_i32(dst, b);
+			gen_helper_lz(dst, b);
 			break;
 		case CC_OP_MULS:
 			t_gen_muls(dst, cpu_PR[PR_MOF], a, b);