target-m68k: define 96bit FP registers for gdb on 680x0

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Message-Id: <20170620205121.26515-5-laurent@vivier.eu>

configure

@@ -6066,7 +6066,7 @@ case "$target_name" in
   ;;
   m68k)
     bflt="yes"
-    gdb_xml_files="cf-core.xml cf-fp.xml"
+    gdb_xml_files="cf-core.xml cf-fp.xml m68k-fp.xml"
   ;;
   microblaze|microblazeel)
     TARGET_ARCH=microblaze

gdb-xml/m68k-fp.xml

@@ -0,0 +1,21 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2008 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.coldfire.fp">
+  <reg name="fp0" bitsize="96" type="float" group="float"/>
+  <reg name="fp1" bitsize="96" type="float" group="float"/>
+  <reg name="fp2" bitsize="96" type="float" group="float"/>
+  <reg name="fp3" bitsize="96" type="float" group="float"/>
+  <reg name="fp4" bitsize="96" type="float" group="float"/>
+  <reg name="fp5" bitsize="96" type="float" group="float"/>
+  <reg name="fp6" bitsize="96" type="float" group="float"/>
+  <reg name="fp7" bitsize="96" type="float" group="float"/>
+
+  <reg name="fpcontrol" bitsize="32" group="float"/>
+  <reg name="fpstatus" bitsize="32" group="float"/>,
+  <reg name="fpiaddr" bitsize="32" type="code_ptr" group="float"/>
+</feature>

target/m68k/helper.c

@@ -102,6 +102,48 @@ static int cf_fpu_gdb_set_reg(CPUM68KState *env, uint8_t *mem_buf, int n)
     return 0;
 }
 
+static int m68k_fpu_gdb_get_reg(CPUM68KState *env, uint8_t *mem_buf, int n)
+{
+    if (n < 8) {
+        stw_be_p(mem_buf, env->fregs[n].l.upper);
+        memset(mem_buf + 2, 0, 2);
+        stq_be_p(mem_buf + 4, env->fregs[n].l.lower);
+        return 12;
+    }
+    switch (n) {
+    case 8: /* fpcontrol */
+        stl_be_p(mem_buf, env->fpcr);
+        return 4;
+    case 9: /* fpstatus */
+        stl_be_p(mem_buf, env->fpsr);
+        return 4;
+    case 10: /* fpiar, not implemented */
+        memset(mem_buf, 0, 4);
+        return 4;
+    }
+    return 0;
+}
+
+static int m68k_fpu_gdb_set_reg(CPUM68KState *env, uint8_t *mem_buf, int n)
+{
+    if (n < 8) {
+        env->fregs[n].l.upper = lduw_be_p(mem_buf);
+        env->fregs[n].l.lower = ldq_be_p(mem_buf + 4);
+        return 12;
+    }
+    switch (n) {
+    case 8: /* fpcontrol */
+        env->fpcr = ldl_p(mem_buf);
+        return 4;
+    case 9: /* fpstatus */
+        env->fpsr = ldl_p(mem_buf);
+        return 4;
+    case 10: /* fpiar, not implemented */
+        return 4;
+    }
+    return 0;
+}
+
 M68kCPU *cpu_m68k_init(const char *cpu_model)
 {
     M68kCPU *cpu;
@@ -130,6 +172,9 @@ void m68k_cpu_init_gdb(M68kCPU *cpu)
     if (m68k_feature(env, M68K_FEATURE_CF_FPU)) {
         gdb_register_coprocessor(cs, cf_fpu_gdb_get_reg, cf_fpu_gdb_set_reg,
                                  11, "cf-fp.xml", 18);
+    } else if (m68k_feature(env, M68K_FEATURE_FPU)) {
+        gdb_register_coprocessor(cs, m68k_fpu_gdb_get_reg,
+                                 m68k_fpu_gdb_set_reg, 11, "m68k-fp.xml", 18);
     }
     /* TODO: Add [E]MAC registers.  */
 }