From 32e9e175767bd382ea5dc6975c4d396f535e8b7f Mon Sep 17 00:00:00 2001
From: Lucien Murray-Pitts <lucienmp.qemu@gmail.com>
Date: Fri, 12 Mar 2021 14:34:12 -0500
Subject: [PATCH] m68k: improve cpu instantiation comments

Improvement in comments for the instantiation functions.
This is to highlight what each cpu class, in the 68000 series, contains
in terms of instructions/features.

Backports ee2fc6c6da8b2d6f961c8559d62e990c65f67736
---
 qemu/target/m68k/cpu.c | 44 ++++++++++++++++++++++++++++++++++++++++++
 qemu/target/m68k/cpu.h |  9 +++++++++
 2 files changed, 53 insertions(+)

diff --git a/qemu/target/m68k/cpu.c b/qemu/target/m68k/cpu.c
index ddd50419..73d99eb2 100644
--- a/qemu/target/m68k/cpu.c
+++ b/qemu/target/m68k/cpu.c
@@ -99,6 +99,7 @@ static void m5206_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
     m68k_set_feature(env, M68K_FEATURE_CF_ISA_A);
 }
 
+/* Base feature set, including isns. for m68k family */
 static void m68000_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     M68kCPU *cpu = M68K_CPU(uc, obj);
@@ -131,6 +132,13 @@ static void m680x0_cpu_common(CPUM68KState *env)
     m68k_set_feature(env, M68K_FEATURE_MOVEP);
 }
 
+/*
+ * Adds BFCHG, BFCLR, BFEXTS, BFEXTU, BFFFO, BFINS, BFSET, BFTST, CAS, CAS2,
+ *      CHK2, CMP2, DIVSL, DIVUL, EXTB, PACK, TRAPcc, UNPK.
+ *
+ * 68020/30 only:
+ *      CALLM, cpBcc, cpDBcc, cpGEN, cpRESTORE, cpSAVE, cpScc, cpTRAPcc
+ */
 static void m68020_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     M68kCPU *cpu = M68K_CPU(uc, obj);
@@ -140,6 +148,14 @@ static void m68020_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
     m68k_set_feature(env, M68K_FEATURE_M68020);
 }
 
+/*
+ * Adds: PFLUSH (*5)
+ * 68030 Only: PFLUSHA (*5), PLOAD (*5), PMOVE
+ * 68030/40 Only: PTEST
+ *
+ * NOTES:
+ *  5. Not valid on MC68EC030
+ */
 static void m68030_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     M68kCPU *cpu = M68K_CPU(uc, obj);
@@ -149,6 +165,23 @@ static void m68030_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
     m68k_set_feature(env, M68K_FEATURE_M68030);
 }
 
+/*
+ * Adds: CINV, CPUSH
+ * Adds all with Note *2: FABS, FSABS, FDABS, FADD, FSADD, FDADD, FBcc, FCMP,
+ *                        FDBcc, FDIV, FSDIV, FDDIV, FMOVE, FSMOVE, FDMOVE,
+ *                        FMOVEM, FMUL, FSMUL, FDMUL, FNEG, FSNEG, FDNEG, FNOP,
+ *                        FRESTORE, FSAVE, FScc, FSQRT, FSSQRT, FDSQRT, FSUB,
+ *                        FSSUB, FDSUB, FTRAPcc, FTST
+ *
+ * Adds with Notes *2, and *3: FACOS, FASIN, FATAN, FATANH, FCOS, FCOSH, FETOX,
+ *                             FETOXM, FGETEXP, FGETMAN, FINT, FINTRZ, FLOG10,
+ *                             FLOG2, FLOGN, FLOGNP1, FMOD, FMOVECR, FREM,
+ *                             FSCALE, FSGLDIV, FSGLMUL, FSIN, FSINCOS, FSINH,
+ *                             FTAN, FTANH, FTENTOX, FTWOTOX
+ * NOTES:
+ * 2. Not applicable to the MC68EC040, MC68LC040, MC68EC060, and MC68LC060.
+ * 3. These are software-supported instructions on the MC68040 and MC68060.
+ */
 static void m68040_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     M68kCPU *cpu = M68K_CPU(uc, obj);
@@ -158,6 +191,17 @@ static void m68040_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
     m68k_set_feature(env, M68K_FEATURE_M68040);
 }
 
+/*
+ * Adds: PLPA
+ * Adds all with Note *2: CAS, CAS2, MULS, MULU, CHK2, CMP2, DIVS, DIVU
+ * All Fxxxx instructions are as per m68040 with exception to; FMOVEM NOTE3
+ *
+ * Does NOT implement MOVEP
+ *
+ * NOTES:
+ * 2. Not applicable to the MC68EC040, MC68LC040, MC68EC060, and MC68LC060.
+ * 3. These are software-supported instructions on the MC68040 and MC68060.
+ */
 static void m68060_cpu_initfn(struct uc_struct *uc, Object *obj, void *opaque)
 {
     M68kCPU *cpu = M68K_CPU(uc, obj);
diff --git a/qemu/target/m68k/cpu.h b/qemu/target/m68k/cpu.h
index 916c5798..2c50ece0 100644
--- a/qemu/target/m68k/cpu.h
+++ b/qemu/target/m68k/cpu.h
@@ -445,6 +445,15 @@ void m68k_switch_sp(CPUM68KState *env);
 void do_m68k_semihosting(CPUM68KState *env, int nr);
 
 /*
+ * The 68000 family is defined in six main CPU classes, the 680[012346]0.
+ * Generally each successive CPU adds enhanced data/stack/instructions.
+ * However, some features are only common to one, or a few classes.
+ * The features covers those subsets of instructons.
+ *
+ * CPU32/32+ are basically 680010 compatible with some 68020 class instructons,
+ * and some additional CPU32 instructions. Mostly Supervisor state differences.
+ *
+ * The ColdFire core ISA is a RISC-style reduction of the 68000 series cpu.
  * There are 4 ColdFire core ISA revisions: A, A+, B and C.
  * Each feature covers the subset of instructions common to the
  * ISA revisions mentioned.