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[Qemu-devel] [patch] Fix extlh instruction on Alpha


From: Vince Weaver
Subject: [Qemu-devel] [patch] Fix extlh instruction on Alpha
Date: Tue, 4 Aug 2009 23:26:43 -0400 (EDT)

Hello

The extlh instruction on Alpha currently doesn't work properly.
It's a combination of a cut/paste bug (16 where it should be 32) as well 
as a "shift by 64" bug.

Below is a patch that fixes the problem, and attached is a test case that 
exhibits the bug.  The program should print a 4-char wide sliding window 
across the test string; without the patch this fails.

Vince

Signed-off-by: Vince Weaver <address@hidden>

diff --git a/target-alpha/translate.c b/target-alpha/translate.c
index 1fc5119..2a681b0 100644
--- a/target-alpha/translate.c
+++ b/target-alpha/translate.c
@@ -526,14 +526,24 @@ static always_inline void gen_ext_h(void 
(*tcg_gen_ext_i64)(TCGv t0, TCGv t1),
             else
                 tcg_gen_mov_i64(cpu_ir[rc], cpu_ir[ra]);
         } else {
+            int l1;
             TCGv tmp1, tmp2;
             tmp1 = tcg_temp_new();
+            l1 = gen_new_label();
+
             tcg_gen_andi_i64(tmp1, cpu_ir[rb], 7);
             tcg_gen_shli_i64(tmp1, tmp1, 3);
+
+            tcg_gen_mov_i64(cpu_ir[rc], cpu_ir[ra]);
+            tcg_gen_brcondi_i64(TCG_COND_EQ, tmp1, 0, l1);
+
             tmp2 = tcg_const_i64(64);
             tcg_gen_sub_i64(tmp1, tmp2, tmp1);
             tcg_temp_free(tmp2);
             tcg_gen_shl_i64(cpu_ir[rc], cpu_ir[ra], tmp1);
+
+            gen_set_label(l1);
+
             tcg_temp_free(tmp1);
         }
         if (tcg_gen_ext_i64)
@@ -1320,7 +1330,7 @@ static always_inline int translate_one (DisasContext 
*ctx, uint32_t insn)
             break;
         case 0x6A:
             /* EXTLH */
-            gen_ext_h(&tcg_gen_ext16u_i64, ra, rb, rc, islit, lit);
+            gen_ext_h(&tcg_gen_ext32u_i64, ra, rb, rc, islit, lit);
             break;
         case 0x72:
             /* MSKQH */

Attachment: uldl.s
Description: Text document

Attachment: uldl
Description: Binary data


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