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[PATCH] target/m68k: only change valid bits in CACR

Laurent Vivier posted 1 patch 4 years, 4 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20191212194045.12882-1-laurent@vivier.eu
Maintainers: Laurent Vivier <laurent@vivier.eu>
There is a newer version of this series
target/m68k/cpu.c    | 28 ++++++++++++++++++++++------
target/m68k/cpu.h    |  4 ++++
target/m68k/helper.c | 16 ++++++++++++++--
3 files changed, 40 insertions(+), 8 deletions(-)
[PATCH] target/m68k: only change valid bits in CACR
Posted by Laurent Vivier 4 years, 4 months ago 
This is used by netBSD (and MacOS ROM) to detect the MMU type

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 target/m68k/cpu.c    | 28 ++++++++++++++++++++++------
 target/m68k/cpu.h    |  4 ++++
 target/m68k/helper.c | 16 ++++++++++++++--
 3 files changed, 40 insertions(+), 8 deletions(-)

diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index e6596de29c..1d202cec49 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -114,11 +114,8 @@ static void m68000_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_MOVEP);
 }
 
-static void m68020_cpu_initfn(Object *obj)
+static void m680x0_cpu_common(CPUM68KState *env)
 {
-    M68kCPU *cpu = M68K_CPU(obj);
-    CPUM68KState *env = &cpu->env;
-
     m68k_set_feature(env, M68K_FEATURE_M68000);
     m68k_set_feature(env, M68K_FEATURE_USP);
     m68k_set_feature(env, M68K_FEATURE_WORD_INDEX);
@@ -136,14 +133,32 @@ static void m68020_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_CHK2);
     m68k_set_feature(env, M68K_FEATURE_MOVEP);
 }
-#define m68030_cpu_initfn m68020_cpu_initfn
+
+static void m68020_cpu_initfn(Object *obj)
+{
+    M68kCPU *cpu = M68K_CPU(obj);
+    CPUM68KState *env = &cpu->env;
+
+    m680x0_cpu_common(env);
+    m68k_set_feature(env, M68K_FEATURE_MMU68851);
+}
+
+static void m68030_cpu_initfn(Object *obj)
+{
+    M68kCPU *cpu = M68K_CPU(obj);
+    CPUM68KState *env = &cpu->env;
+
+    m680x0_cpu_common(env);
+    m68k_set_feature(env, M68K_FEATURE_MMU68030);
+}
 
 static void m68040_cpu_initfn(Object *obj)
 {
     M68kCPU *cpu = M68K_CPU(obj);
     CPUM68KState *env = &cpu->env;
 
-    m68020_cpu_initfn(obj);
+    m680x0_cpu_common(env);
+    m68k_set_feature(env, M68K_FEATURE_MMU68040);
     m68k_set_feature(env, M68K_FEATURE_M68040);
 }
 
@@ -166,6 +181,7 @@ static void m68060_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_BKPT);
     m68k_set_feature(env, M68K_FEATURE_RTD);
     m68k_set_feature(env, M68K_FEATURE_CHK2);
+    m68k_set_feature(env, M68K_FEATURE_MMU68060);
 }
 
 static void m5208_cpu_initfn(Object *obj)
diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
index 20de3c379a..36e4353b44 100644
--- a/target/m68k/cpu.h
+++ b/target/m68k/cpu.h
@@ -483,6 +483,10 @@ enum m68k_features {
     M68K_FEATURE_CHK2,
     M68K_FEATURE_M68040, /* instructions specific to MC68040 */
     M68K_FEATURE_MOVEP,
+    M68K_FEATURE_MMU68851,
+    M68K_FEATURE_MMU68030,
+    M68K_FEATURE_MMU68040,
+    M68K_FEATURE_MMU68060,
 };
 
 static inline int m68k_feature(CPUM68KState *env, int feature)
diff --git a/target/m68k/helper.c b/target/m68k/helper.c
index ae766a6cb0..b5758bbd7d 100644
--- a/target/m68k/helper.c
+++ b/target/m68k/helper.c
@@ -205,7 +205,13 @@ void HELPER(m68k_movec_to)(CPUM68KState *env, uint32_t reg, uint32_t val)
         return;
     /* MC680[234]0 */
     case M68K_CR_CACR:
-        env->cacr = val;
+        if (m68k_feature(env, M68K_FEATURE_MMU68040)) {
+            env->cacr = val & 0x80008000;
+        } else if (m68k_feature(env, M68K_FEATURE_MMU68030)) {
+            env->cacr = val & 0x00003fff;
+        } else if (m68k_feature(env, M68K_FEATURE_MMU68851)) {
+            env->cacr = val & 0x0000000f;
+        }
         m68k_switch_sp(env);
         return;
     /* MC680[34]0 */
@@ -261,7 +267,13 @@ uint32_t HELPER(m68k_movec_from)(CPUM68KState *env, uint32_t reg)
         return env->vbr;
     /* MC680[234]0 */
     case M68K_CR_CACR:
-        return env->cacr;
+        if (m68k_feature(env, M68K_FEATURE_MMU68040)) {
+            return env->cacr & 0x80008000;
+        } else if (m68k_feature(env, M68K_FEATURE_MMU68030)) {
+            return env->cacr & 0x00003fff;
+        } else if (m68k_feature(env, M68K_FEATURE_MMU68851)) {
+            return env->cacr & 0x0000000f;
+        }
     /* MC680[34]0 */
     case M68K_CR_TC:
         return env->mmu.tcr;
-- 
2.23.0
Re: [PATCH] target/m68k: only change valid bits in CACR
Posted by Thomas Huth 4 years, 4 months ago 
Am Thu, 12 Dec 2019 20:40:45 +0100
schrieb Laurent Vivier <laurent@vivier.eu>:

> This is used by netBSD (and MacOS ROM) to detect the MMU type
> 
> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
> ---
>  target/m68k/cpu.c    | 28 ++++++++++++++++++++++------
>  target/m68k/cpu.h    |  4 ++++
>  target/m68k/helper.c | 16 ++++++++++++++--
>  3 files changed, 40 insertions(+), 8 deletions(-)
> 
> diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
> index e6596de29c..1d202cec49 100644
> --- a/target/m68k/cpu.c
> +++ b/target/m68k/cpu.c
> @@ -114,11 +114,8 @@ static void m68000_cpu_initfn(Object *obj)
>      m68k_set_feature(env, M68K_FEATURE_MOVEP);
>  }
>  
> -static void m68020_cpu_initfn(Object *obj)
> +static void m680x0_cpu_common(CPUM68KState *env)
>  {
> -    M68kCPU *cpu = M68K_CPU(obj);
> -    CPUM68KState *env = &cpu->env;
> -
>      m68k_set_feature(env, M68K_FEATURE_M68000);
>      m68k_set_feature(env, M68K_FEATURE_USP);
>      m68k_set_feature(env, M68K_FEATURE_WORD_INDEX);
> @@ -136,14 +133,32 @@ static void m68020_cpu_initfn(Object *obj)
>      m68k_set_feature(env, M68K_FEATURE_CHK2);
>      m68k_set_feature(env, M68K_FEATURE_MOVEP);
>  }
> -#define m68030_cpu_initfn m68020_cpu_initfn
> +
> +static void m68020_cpu_initfn(Object *obj)
> +{
> +    M68kCPU *cpu = M68K_CPU(obj);
> +    CPUM68KState *env = &cpu->env;
> +
> +    m680x0_cpu_common(env);
> +    m68k_set_feature(env, M68K_FEATURE_MMU68851);
> +}
> +
> +static void m68030_cpu_initfn(Object *obj)
> +{
> +    M68kCPU *cpu = M68K_CPU(obj);
> +    CPUM68KState *env = &cpu->env;
> +
> +    m680x0_cpu_common(env);
> +    m68k_set_feature(env, M68K_FEATURE_MMU68030);
> +}
>  
>  static void m68040_cpu_initfn(Object *obj)
>  {
>      M68kCPU *cpu = M68K_CPU(obj);
>      CPUM68KState *env = &cpu->env;
>  
> -    m68020_cpu_initfn(obj);
> +    m680x0_cpu_common(env);
> +    m68k_set_feature(env, M68K_FEATURE_MMU68040);
>      m68k_set_feature(env, M68K_FEATURE_M68040);
>  }
>  
> @@ -166,6 +181,7 @@ static void m68060_cpu_initfn(Object *obj)
>      m68k_set_feature(env, M68K_FEATURE_BKPT);
>      m68k_set_feature(env, M68K_FEATURE_RTD);
>      m68k_set_feature(env, M68K_FEATURE_CHK2);
> +    m68k_set_feature(env, M68K_FEATURE_MMU68060);
>  }
>  
>  static void m5208_cpu_initfn(Object *obj)
> diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h
> index 20de3c379a..36e4353b44 100644
> --- a/target/m68k/cpu.h
> +++ b/target/m68k/cpu.h
> @@ -483,6 +483,10 @@ enum m68k_features {
>      M68K_FEATURE_CHK2,
>      M68K_FEATURE_M68040, /* instructions specific to MC68040 */
>      M68K_FEATURE_MOVEP,
> +    M68K_FEATURE_MMU68851,
> +    M68K_FEATURE_MMU68030,
> +    M68K_FEATURE_MMU68040,
> +    M68K_FEATURE_MMU68060,
>  };
>  
>  static inline int m68k_feature(CPUM68KState *env, int feature)
> diff --git a/target/m68k/helper.c b/target/m68k/helper.c
> index ae766a6cb0..b5758bbd7d 100644
> --- a/target/m68k/helper.c
> +++ b/target/m68k/helper.c
> @@ -205,7 +205,13 @@ void HELPER(m68k_movec_to)(CPUM68KState *env,
> uint32_t reg, uint32_t val) return;
>      /* MC680[234]0 */
>      case M68K_CR_CACR:
> -        env->cacr = val;
> +        if (m68k_feature(env, M68K_FEATURE_MMU68040)) {

Why is the *Cache* control register tied to an MMU feature?
Maybe use M68K_FEATURE_M68040 instead? Or call the new flag
M68K_FEATURE_CACHE040 instead?

> +            env->cacr = val & 0x80008000;
> +        } else if (m68k_feature(env, M68K_FEATURE_MMU68030)) {
> +            env->cacr = val & 0x00003fff;

That seems to be too much, according to my MC68030 UM, there are some
bits tied to zero inbetween. The correct mask should be 0x3f1f, I think.

> +        } else if (m68k_feature(env, M68K_FEATURE_MMU68851)) {
> +            env->cacr = val & 0x0000000f;
> +        }

What about the 68060? It has yet another set of bits in the CACR...

>          m68k_switch_sp(env);
>          return;
>      /* MC680[34]0 */
> @@ -261,7 +267,13 @@ uint32_t HELPER(m68k_movec_from)(CPUM68KState
> *env, uint32_t reg) return env->vbr;
>      /* MC680[234]0 */
>      case M68K_CR_CACR:
> -        return env->cacr;
> +        if (m68k_feature(env, M68K_FEATURE_MMU68040)) {
> +            return env->cacr & 0x80008000;
> +        } else if (m68k_feature(env, M68K_FEATURE_MMU68030)) {
> +            return env->cacr & 0x00003fff;
> +        } else if (m68k_feature(env, M68K_FEATURE_MMU68851)) {
> +            return env->cacr & 0x0000000f;
> +        }

Wouldn't it be enough to do the masking either only during the "from"
or during the "to" move? If you want to do it for both, I'd suggest to
declare a little helper function for the masking instead, so that you
don't have to repeat the code.

 Thomas

Patchew 2.1-devel-0870f84

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