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[Qemu-devel] [PATCH v2 05/10] target-arm: optimize arm load/store multip


From: juha . riihimaki
Subject: [Qemu-devel] [PATCH v2 05/10] target-arm: optimize arm load/store multiple ops
Date: Sat, 24 Oct 2009 15:19:04 +0300

From: Juha Riihimäki <address@hidden>

RM load/store multiple instructions can be slightly optimized by
loading the register offset constant into a variable outside the
register loop and using the preloaded variable inside the loop instead
of reloading the offset value to a temporary variable on each loop
iteration. This causes less TCG ops to be generated for a ARM load/
store multiple instruction if there are more than one register
accessed, otherwise the number of generated TCG ops is the same.

Signed-off-by: Juha Riihimäki <address@hidden>
Acked-by: Laurent Desnogues <address@hidden>
---
 target-arm/translate.c |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/target-arm/translate.c b/target-arm/translate.c
index 38fb833..d1e2ed2 100644
--- a/target-arm/translate.c
+++ b/target-arm/translate.c
@@ -6852,6 +6852,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
                 }
                 rn = (insn >> 16) & 0xf;
                 addr = load_reg(s, rn);
+                tmp2 = tcg_const_i32(4);
 
                 /* compute total size */
                 loaded_base = 0;
@@ -6865,7 +6866,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
                 if (insn & (1 << 23)) {
                     if (insn & (1 << 24)) {
                         /* pre increment */
-                        tcg_gen_addi_i32(addr, addr, 4);
+                        tcg_gen_add_i32(addr, addr, tmp2);
                     } else {
                         /* post increment */
                     }
@@ -6918,7 +6919,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
                         j++;
                         /* no need to add after the last transfer */
                         if (j != n)
-                            tcg_gen_addi_i32(addr, addr, 4);
+                            tcg_gen_add_i32(addr, addr, tmp2);
                     }
                 }
                 if (insn & (1 << 21)) {
@@ -6928,7 +6929,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
                             /* pre increment */
                         } else {
                             /* post increment */
-                            tcg_gen_addi_i32(addr, addr, 4);
+                            tcg_gen_add_i32(addr, addr, tmp2);
                         }
                     } else {
                         if (insn & (1 << 24)) {
@@ -6944,6 +6945,7 @@ static void disas_arm_insn(CPUState * env, DisasContext 
*s)
                 } else {
                     dead_tmp(addr);
                 }
+                tcg_temp_free_i32(tmp2);
                 if (loaded_base) {
                     store_reg(s, rn, loaded_var);
                 }
-- 
1.6.5





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