[Qemu-devel] [PATCH] ARM7TDMI emulation

[Ulrich Hecht <uli@suse.de>]

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Hi!

This patch adds ARM7TDMI emulation with Thumb v1 (no BLX, no BKPT, ignore 
bit 0 on POP PC) and without CP15.

CU
Uli

-- 
SUSE LINUX Products GmbH, GF: Markus Rex, HRB 16746 (AG Nürnberg)

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[-- Type: text/x-diff, Size: 4341 bytes --]

Index: cpu.h
===================================================================
RCS file: /sources/qemu/qemu/target-arm/cpu.h,v
retrieving revision 1.28
diff -u -r1.28 cpu.h
--- cpu.h	24 Jun 2007 12:09:48 -0000	1.28
+++ cpu.h	2 Jul 2007 13:16:12 -0000
@@ -247,7 +247,9 @@
     ARM_FEATURE_AUXCR,  /* ARM1026 Auxiliary control register.  */
     ARM_FEATURE_XSCALE, /* Intel XScale extensions.  */
     ARM_FEATURE_IWMMXT, /* Intel iwMMXt extension.  */
-    ARM_FEATURE_MPU     /* Only has Memory Protection Unit, not full MMU.  */
+    ARM_FEATURE_MPU,    /* Only has Memory Protection Unit, not full MMU.  */
+    ARM_FEATURE_THUMB1, /* Thumb v1 (ARM v4 with Thumb) */
+    ARM_FEATURE_NO_CP15 /* ARM7TDMI, ARM7TDMI-S, ARM7EJ-S, and ARM9TDMI cores do not have a CP15 */
 };
 
 static inline int arm_feature(CPUARMState *env, int feature)
@@ -262,6 +264,7 @@
                        ARMReadCPFunc *cp_read, ARMWriteCPFunc *cp_write,
                        void *opaque);
 
+#define ARM_CPUID_ARM7TDMI  0x41807000 /* guess; no CP15 on ARM7TDMI */
 #define ARM_CPUID_ARM1026   0x4106a262
 #define ARM_CPUID_ARM926    0x41069265
 #define ARM_CPUID_ARM946    0x41059461
Index: helper.c
===================================================================
RCS file: /sources/qemu/qemu/target-arm/helper.c,v
retrieving revision 1.17
diff -u -r1.17 helper.c
--- helper.c	24 Jun 2007 12:09:48 -0000	1.17
+++ helper.c	2 Jul 2007 13:16:12 -0000
@@ -14,6 +14,11 @@
 {
     env->cp15.c0_cpuid = id;
     switch (id) {
+    case ARM_CPUID_ARM7TDMI:
+        set_feature(env, ARM_FEATURE_THUMB1);
+        set_feature(env, ARM_FEATURE_NO_CP15);
+        /* no CP15 here */
+        break;
     case ARM_CPUID_ARM926:
         set_feature(env, ARM_FEATURE_VFP);
         env->vfp.xregs[ARM_VFP_FPSID] = 0x41011090;
@@ -98,6 +103,7 @@
 };
 
 static const struct arm_cpu_t arm_cpu_names[] = {
+    { ARM_CPUID_ARM7TDMI, "arm7tdmi"},
     { ARM_CPUID_ARM926, "arm926"},
     { ARM_CPUID_ARM946, "arm946"},
     { ARM_CPUID_ARM1026, "arm1026"},
Index: translate.c
===================================================================
RCS file: /sources/qemu/qemu/target-arm/translate.c,v
retrieving revision 1.53
diff -u -r1.53 translate.c
--- translate.c	11 Jun 2007 18:59:35 -0000	1.53
+++ translate.c	2 Jul 2007 13:16:13 -0000
@@ -1589,7 +1589,7 @@
     uint32_t rd;
 
     /* ??? Some cp15 registers are accessible from userspace.  */
-    if (IS_USER(s)) {
+    if (IS_USER(s) || arm_feature(env, ARM_FEATURE_NO_CP15)) {
         return 1;
     }
     if ((insn & 0x0fff0fff) == 0x0e070f90
@@ -2958,7 +2958,7 @@
     }
 }
 
-static void disas_thumb_insn(DisasContext *s)
+static void disas_thumb_insn(CPUState *env, DisasContext *s)
 {
     uint32_t val, insn, op, rm, rn, rd, shift, cond;
     int32_t offset;
@@ -3058,6 +3058,7 @@
                 break;
             case 3:/* branch [and link] exchange thumb register */
                 if (insn & (1 << 7)) {
+                    if(arm_feature(env, ARM_FEATURE_THUMB1)) goto undef;
                     val = (uint32_t)s->pc | 1;
                     gen_op_movl_T1_im(val);
                     gen_movl_reg_T1(s, 14);
@@ -3367,11 +3368,16 @@
             /* write back the new stack pointer */
             gen_movl_reg_T1(s, 13);
             /* set the new PC value */
-            if ((insn & 0x0900) == 0x0900)
-                gen_bx(s);
+            if ((insn & 0x0900) == 0x0900) {
+                if(arm_feature(env, ARM_FEATURE_THUMB1))
+                  gen_movl_reg_T0(s, 15);
+                else
+                  gen_bx(s);
+            }
             break;
 
         case 0xe: /* bkpt */
+            if(arm_feature(env, ARM_FEATURE_THUMB1)) goto undef;
             gen_op_movl_T0_im((long)s->pc - 2);
             gen_op_movl_reg_TN[0][15]();
             gen_op_bkpt();
@@ -3442,6 +3448,7 @@
         /* unconditional branch */
         if (insn & (1 << 11)) {
             /* Second half of blx.  */
+            if(arm_feature(env, ARM_FEATURE_THUMB1)) goto undef;
             offset = ((insn & 0x7ff) << 1);
             gen_movl_T0_reg(s, 14);
             gen_op_movl_T1_im(offset);
@@ -3571,7 +3578,7 @@
         }
 
         if (env->thumb)
-          disas_thumb_insn(dc);
+          disas_thumb_insn(env, dc);
         else
           disas_arm_insn(env, dc);