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[Qemu-devel] [PATCH] alpha ldl_l stl_c fix
From: |
Vince Weaver |
Subject: |
[Qemu-devel] [PATCH] alpha ldl_l stl_c fix |
Date: |
Thu, 6 Nov 2008 23:10:54 -0500 (EST) |
Hello
The following patch is needed for a hello world binary to run under
alpha-linux-user.
The issue is the ldl_l and stl_c instructions. The current implementation
is a bit confused.
ldl_l should set the lock bit, and write the address to a table
stl_c should write to memory only if lock bit is set, then return the
lock_bit, then reset the lock_bit to zero
The current code does a weird mix of these things that don't seem to work.
This patch fixes things enough for me for hello_world to work, but it
still isn't correct if we ever want to use these instructions to implement
atomic loads/stores or run multithreaded code.
Note... the patch includes a commented out branch. For proper emulation
that branch should be included, but for some reason on my x86_64 system if
the branch is included, then the memory address calculation is converted
to nops for some reason (leading to a segfault). I'm not sure why that is
happening.
Vince
Index: target-alpha/translate.c
===================================================================
--- target-alpha/translate.c (revision 5643)
+++ target-alpha/translate.c (working copy)
@@ -138,13 +138,13 @@
static always_inline void gen_qemu_ldl_l (TCGv t0, TCGv t1, int flags)
{
- tcg_gen_mov_i64(cpu_lock, t1);
+ tcg_gen_movi_i64(cpu_lock, 1);
tcg_gen_qemu_ld32s(t0, t1, flags);
}
static always_inline void gen_qemu_ldq_l (TCGv t0, TCGv t1, int flags)
{
- tcg_gen_mov_i64(cpu_lock, t1);
+ tcg_gen_movi_i64(cpu_lock, 1);
tcg_gen_qemu_ld64(t0, t1, flags);
}
@@ -201,34 +201,27 @@
static always_inline void gen_qemu_stl_c (TCGv t0, TCGv t1, int flags)
{
- int l1, l2;
+ int l1;
l1 = gen_new_label();
- l2 = gen_new_label();
- tcg_gen_brcond_i64(TCG_COND_NE, cpu_lock, t1, l1);
+// tcg_gen_brcondi_i64(TCG_COND_EQ, cpu_lock, 0, l1);
tcg_gen_qemu_st32(t0, t1, flags);
- tcg_gen_movi_i64(t0, 0);
- tcg_gen_br(l2);
gen_set_label(l1);
- tcg_gen_movi_i64(t0, 1);
- gen_set_label(l2);
- tcg_gen_movi_i64(cpu_lock, -1);
+ tcg_gen_mov_i64(t0, cpu_lock);
+ tcg_gen_movi_i64(cpu_lock, 0);
+
}
static always_inline void gen_qemu_stq_c (TCGv t0, TCGv t1, int flags)
{
- int l1, l2;
+ int l1;
l1 = gen_new_label();
- l2 = gen_new_label();
- tcg_gen_brcond_i64(TCG_COND_NE, cpu_lock, t1, l1);
+// tcg_gen_brcondi_i64(TCG_COND_EQ, cpu_lock, 0, l1);
tcg_gen_qemu_st64(t0, t1, flags);
- tcg_gen_movi_i64(t0, 0);
- tcg_gen_br(l2);
gen_set_label(l1);
- tcg_gen_movi_i64(t0, 1);
- gen_set_label(l2);
- tcg_gen_movi_i64(cpu_lock, -1);
+ tcg_gen_movi_i64(t0, cpu_lock);
+ tcg_gen_movi_i64(cpu_lock, 0);
}
static always_inline void gen_store_mem (DisasContext *ctx,
- [Qemu-devel] [PATCH] alpha ldl_l stl_c fix,
Vince Weaver <=