target-i386: Rewrite gen_enter inline

Use gen_lea_v_seg for centralized segment base knowledge.  Unify
code across 32- and 64-bit.  Fix note about "must save state"
before using the out-of-line helpers.

Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1450379966-28198-8-git-send-email-rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 34 insertions, 137 deletions

diff --git a/target-i386/helper.h b/target-i386/helper.h
index ecfcfd1..3a25c3b 100644
--- a/target-i386/helper.h
+++ b/target-i386/helper.h
@@ -44,10 +44,6 @@ DEF_HELPER_FLAGS_3(set_dr, TCG_CALL_NO_WG, void, env, int, tl)
 DEF_HELPER_FLAGS_2(get_dr, TCG_CALL_NO_WG, tl, env, int)
 DEF_HELPER_2(invlpg, void, env, tl)
 
-DEF_HELPER_4(enter_level, void, env, int, int, tl)
-#ifdef TARGET_X86_64
-DEF_HELPER_4(enter64_level, void, env, int, int, tl)
-#endif
 DEF_HELPER_1(sysenter, void, env)
 DEF_HELPER_2(sysexit, void, env, int)
 #ifdef TARGET_X86_64
diff --git a/target-i386/seg_helper.c b/target-i386/seg_helper.c
index 4f26941..b5f3d72 100644
--- a/target-i386/seg_helper.c
+++ b/target-i386/seg_helper.c
@@ -1379,80 +1379,6 @@ bool x86_cpu_exec_interrupt(CPUState *cs, int interrupt_request)
     return ret;
 }
 
-void helper_enter_level(CPUX86State *env, int level, int data32,
-                        target_ulong t1)
-{
-    target_ulong ssp;
-    uint32_t esp_mask, esp, ebp;
-
-    esp_mask = get_sp_mask(env->segs[R_SS].flags);
-    ssp = env->segs[R_SS].base;
-    ebp = env->regs[R_EBP];
-    esp = env->regs[R_ESP];
-    if (data32) {
-        /* 32 bit */
-        esp -= 4;
-        while (--level) {
-            esp -= 4;
-            ebp -= 4;
-            cpu_stl_data_ra(env, ssp + (esp & esp_mask),
-                            cpu_ldl_data_ra(env, ssp + (ebp & esp_mask),
-                                            GETPC()),
-                            GETPC());
-        }
-        esp -= 4;
-        cpu_stl_data_ra(env, ssp + (esp & esp_mask), t1, GETPC());
-    } else {
-        /* 16 bit */
-        esp -= 2;
-        while (--level) {
-            esp -= 2;
-            ebp -= 2;
-            cpu_stw_data_ra(env, ssp + (esp & esp_mask),
-                            cpu_lduw_data_ra(env, ssp + (ebp & esp_mask),
-                                             GETPC()),
-                            GETPC());
-        }
-        esp -= 2;
-        cpu_stw_data_ra(env, ssp + (esp & esp_mask), t1, GETPC());
-    }
-}
-
-#ifdef TARGET_X86_64
-void helper_enter64_level(CPUX86State *env, int level, int data64,
-                          target_ulong t1)
-{
-    target_ulong esp, ebp;
-
-    ebp = env->regs[R_EBP];
-    esp = env->regs[R_ESP];
-
-    if (data64) {
-        /* 64 bit */
-        esp -= 8;
-        while (--level) {
-            esp -= 8;
-            ebp -= 8;
-            cpu_stq_data_ra(env, esp, cpu_ldq_data_ra(env, ebp, GETPC()),
-                            GETPC());
-        }
-        esp -= 8;
-        cpu_stq_data_ra(env, esp, t1, GETPC());
-    } else {
-        /* 16 bit */
-        esp -= 2;
-        while (--level) {
-            esp -= 2;
-            ebp -= 2;
-            cpu_stw_data_ra(env, esp, cpu_lduw_data_ra(env, ebp, GETPC()),
-                            GETPC());
-        }
-        esp -= 2;
-        cpu_stw_data_ra(env, esp, t1, GETPC());
-    }
-}
-#endif
-
 void helper_lldt(CPUX86State *env, int selector)
 {
     SegmentCache *dt;
diff --git a/target-i386/translate.c b/target-i386/translate.c
index 8900a0c..5aeac05 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -373,11 +373,6 @@ static inline void gen_op_mov_v_reg(TCGMemOp ot, TCGv t0, int reg)
     }
 }
 
-static inline void gen_op_movl_A0_reg(int reg)
-{
-    tcg_gen_mov_tl(cpu_A0, cpu_regs[reg]);
-}
-
 static inline void gen_op_addl_A0_im(int32_t val)
 {
     tcg_gen_addi_tl(cpu_A0, cpu_A0, val);
@@ -420,17 +415,6 @@ static inline void gen_op_add_reg_T0(TCGMemOp size, int reg)
     gen_op_mov_reg_v(size, reg, cpu_tmp0);
 }
 
-static inline void gen_op_addl_A0_seg(DisasContext *s, int reg)
-{
-    if (CODE64(s)) {
-        tcg_gen_ext32u_tl(cpu_A0, cpu_A0);
-        tcg_gen_add_tl(cpu_A0, cpu_A0, cpu_seg_base[reg]);
-    } else {
-        tcg_gen_add_tl(cpu_A0, cpu_A0, cpu_seg_base[reg]);
-        tcg_gen_ext32u_tl(cpu_A0, cpu_A0);
-    }
-}
-
 static inline void gen_op_ld_v(DisasContext *s, int idx, TCGv t0, TCGv a0)
 {
     tcg_gen_qemu_ld_tl(t0, a0, s->mem_index, idx | MO_LE);
@@ -2337,51 +2321,42 @@ static void gen_popa(DisasContext *s)
 
 static void gen_enter(DisasContext *s, int esp_addend, int level)
 {
-    TCGMemOp ot = mo_pushpop(s, s->dflag);
-    int opsize = 1 << ot;
+    TCGMemOp d_ot = mo_pushpop(s, s->dflag);
+    TCGMemOp a_ot = CODE64(s) ? MO_64 : s->ss32 ? MO_32 : MO_16;
+    int size = 1 << d_ot;
 
-    level &= 0x1f;
-#ifdef TARGET_X86_64
-    if (CODE64(s)) {
-        gen_op_movl_A0_reg(R_ESP);
-        gen_op_addq_A0_im(-opsize);
-        tcg_gen_mov_tl(cpu_T[1], cpu_A0);
-
-        /* push bp */
-        gen_op_mov_v_reg(MO_32, cpu_T[0], R_EBP);
-        gen_op_st_v(s, ot, cpu_T[0], cpu_A0);
-        if (level) {
-            /* XXX: must save state */
-            gen_helper_enter64_level(cpu_env, tcg_const_i32(level),
-                                     tcg_const_i32((ot == MO_64)),
-                                     cpu_T[1]);
-        }
-        gen_op_mov_reg_v(ot, R_EBP, cpu_T[1]);
-        tcg_gen_addi_tl(cpu_T[1], cpu_T[1], -esp_addend + (-opsize * level));
-        gen_op_mov_reg_v(MO_64, R_ESP, cpu_T[1]);
-    } else
-#endif
-    {
-        gen_op_movl_A0_reg(R_ESP);
-        gen_op_addl_A0_im(-opsize);
-        if (!s->ss32)
-            tcg_gen_ext16u_tl(cpu_A0, cpu_A0);
-        tcg_gen_mov_tl(cpu_T[1], cpu_A0);
-        if (s->addseg)
-            gen_op_addl_A0_seg(s, R_SS);
-        /* push bp */
-        gen_op_mov_v_reg(MO_32, cpu_T[0], R_EBP);
-        gen_op_st_v(s, ot, cpu_T[0], cpu_A0);
-        if (level) {
-            /* XXX: must save state */
-            gen_helper_enter_level(cpu_env, tcg_const_i32(level),
-                                   tcg_const_i32(s->dflag - 1),
-                                   cpu_T[1]);
-        }
-        gen_op_mov_reg_v(ot, R_EBP, cpu_T[1]);
-        tcg_gen_addi_tl(cpu_T[1], cpu_T[1], -esp_addend + (-opsize * level));
-        gen_op_mov_reg_v(MO_16 + s->ss32, R_ESP, cpu_T[1]);
+    /* Push BP; compute FrameTemp into T1.  */
+    tcg_gen_subi_tl(cpu_T[1], cpu_regs[R_ESP], size);
+    gen_lea_v_seg(s, a_ot, cpu_T[1], R_SS, -1);
+    gen_op_st_v(s, d_ot, cpu_regs[R_EBP], cpu_A0);
+
+    level &= 31;
+    if (level != 0) {
+        int i;
+
+        /* Copy level-1 pointers from the previous frame.  */
+        for (i = 1; i < level; ++i) {
+            tcg_gen_subi_tl(cpu_A0, cpu_regs[R_EBP], size * i);
+            gen_lea_v_seg(s, a_ot, cpu_A0, R_SS, -1);
+            gen_op_ld_v(s, d_ot, cpu_tmp0, cpu_A0);
+
+            tcg_gen_subi_tl(cpu_A0, cpu_T[1], size * i);
+            gen_lea_v_seg(s, a_ot, cpu_A0, R_SS, -1);
+            gen_op_st_v(s, d_ot, cpu_tmp0, cpu_A0);
+        }
+
+        /* Push the current FrameTemp as the last level.  */
+        tcg_gen_subi_tl(cpu_A0, cpu_T[1], size * level);
+        gen_lea_v_seg(s, a_ot, cpu_A0, R_SS, -1);
+        gen_op_st_v(s, d_ot, cpu_T[1], cpu_A0);
     }
+
+    /* Copy the FrameTemp value to EBP.  */
+    gen_op_mov_reg_v(a_ot, R_EBP, cpu_T[1]);
+
+    /* Compute the final value of ESP.  */
+    tcg_gen_subi_tl(cpu_T[1], cpu_T[1], esp_addend + size * level);
+    gen_op_mov_reg_v(a_ot, R_ESP, cpu_T[1]);
 }
 
 static void gen_exception(DisasContext *s, int trapno, target_ulong cur_eip)