[Qemu-devel] [PATCH 2/6] Cascade m68k_features by m680xx_cpu_initfn() to improve readability

[Lucien Murray-Pitts <lucienmp.qemu@gmail.com>]

The m680XX_cpu_initfn functions have been rearranged to cascade starting from
the base 68000, so that the 68010 then inherits from this, and so on until the
68060.

This makes it simpler to track features since in most cases the m68k were
product enhancements on each other, with only a few instructions being retired.

Because each cpu class inherits the previous CPU class, then for example
the 68020 also has the feature 68010, and 68000 and so on upto the 68060.

- Added 68010 cpu class, and moved correct features into 68000/68010.
- Added m68k_unset_feature to allow removing a feature in the inheritence
- Created real m68030_cpu_initfn to replace the macro define
  for more obvious calling/future expansion

Signed-off-by: Lucien Murray-Pitts <lucienmp.qemu@gmail.com>
---
 target/m68k/cpu.c | 58 +++++++++++++++++++++++++++++------------------
 1 file changed, 36 insertions(+), 22 deletions(-)

diff --git a/target/m68k/cpu.c b/target/m68k/cpu.c
index cc770a8042..f3246d6e72 100644
--- a/target/m68k/cpu.c
+++ b/target/m68k/cpu.c
@@ -42,6 +42,11 @@ static void m68k_set_feature(CPUM68KState *env, int feature)
     env->features |= (1u << feature);
 }
 
+static void m68k_unset_feature(CPUM68KState *env, int feature)
+{
+    env->features &= (-1u - (1u << feature));
+}
+
 /* CPUClass::reset() */
 static void m68k_cpu_reset(CPUState *s)
 {
@@ -119,6 +124,21 @@ static void m68000_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_MOVEP);
 }
 
+
+/*
+ * Adds BKPT, MOVE-from-SR *now priv instr, and MOVEC, MOVES, RTD
+ */
+static void m68010_cpu_initfn(Object *obj)
+{
+    M68kCPU *cpu = M68K_CPU(obj);
+    CPUM68KState *env = &cpu->env;
+
+    m68000_cpu_initfn(obj);
+    m68k_set_feature(env, M68K_FEATURE_RTD);
+    m68k_set_feature(env, M68K_FEATURE_BKPT);
+}
+
+
 /*
  * Adds BFCHG, BFCLR, BFEXTS, BFEXTU, BFFFO, BFINS, BFSET, BFTST, CAS, CAS2,
  *      CHK2, CMP2, DIVSL, DIVUL, EXTB, PACK, TRAPcc, UNPK.
@@ -130,9 +150,7 @@ static void m68020_cpu_initfn(Object *obj)
     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);
+    m68010_cpu_initfn(obj);
     m68k_set_feature(env, M68K_FEATURE_QUAD_MULDIV);
     m68k_set_feature(env, M68K_FEATURE_BRAL);
     m68k_set_feature(env, M68K_FEATURE_BCCL);
@@ -142,10 +160,7 @@ static void m68020_cpu_initfn(Object *obj)
     m68k_set_feature(env, M68K_FEATURE_LONG_MULDIV);
     m68k_set_feature(env, M68K_FEATURE_FPU);
     m68k_set_feature(env, M68K_FEATURE_CAS);
-    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_MOVEP);
 }
 
 /*
@@ -156,7 +171,14 @@ static void m68020_cpu_initfn(Object *obj)
  * NOTES:
  *  5. Not valid on MC68EC030
  */
-#define m68030_cpu_initfn m68020_cpu_initfn
+static void m68030_cpu_initfn(Object *obj)
+{
+    M68kCPU *cpu = M68K_CPU(obj);
+    CPUM68KState *env = &cpu->env;
+
+    m68020_cpu_initfn(obj);
+}
+
 
 /*
  * Adds: CINV, CPUSH
@@ -180,7 +202,7 @@ static void m68040_cpu_initfn(Object *obj)
     M68kCPU *cpu = M68K_CPU(obj);
     CPUM68KState *env = &cpu->env;
 
-    m68020_cpu_initfn(obj);
+    m68030_cpu_initfn(obj);
     m68k_set_feature(env, M68K_FEATURE_M68040);
 }
 
@@ -200,20 +222,11 @@ static void m68060_cpu_initfn(Object *obj)
     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);
-    m68k_set_feature(env, M68K_FEATURE_BRAL);
-    m68k_set_feature(env, M68K_FEATURE_BCCL);
-    m68k_set_feature(env, M68K_FEATURE_BITFIELD);
-    m68k_set_feature(env, M68K_FEATURE_EXT_FULL);
-    m68k_set_feature(env, M68K_FEATURE_SCALED_INDEX);
-    m68k_set_feature(env, M68K_FEATURE_LONG_MULDIV);
-    m68k_set_feature(env, M68K_FEATURE_FPU);
-    m68k_set_feature(env, M68K_FEATURE_CAS);
-    m68k_set_feature(env, M68K_FEATURE_BKPT);
-    m68k_set_feature(env, M68K_FEATURE_RTD);
-    m68k_set_feature(env, M68K_FEATURE_CHK2);
+    m68040_cpu_initfn(obj);
+    m68k_unset_feature(env, M68K_FEATURE_MOVEP);
+
+    /* Implemented as a software feature */
+    m68k_unset_feature(env, M68K_FEATURE_QUAD_MULDIV);
 }
 
 static void m5208_cpu_initfn(Object *obj)
@@ -350,6 +363,7 @@ static const TypeInfo m68k_cpus_type_infos[] = {
         .class_init = m68k_cpu_class_init,
     },
     DEFINE_M68K_CPU_TYPE("m68000", m68000_cpu_initfn),
+    DEFINE_M68K_CPU_TYPE("m68010", m68010_cpu_initfn),
     DEFINE_M68K_CPU_TYPE("m68020", m68020_cpu_initfn),
     DEFINE_M68K_CPU_TYPE("m68030", m68030_cpu_initfn),
     DEFINE_M68K_CPU_TYPE("m68040", m68040_cpu_initfn),
-- 
2.21.0