dbghelp: Implement arm_fetch_context_reg.

dlls/dbghelp/cpu_arm.c

@@ -63,7 +63,30 @@ static unsigned arm_map_dwarf_register(unsigned regno)
 
 static void* arm_fetch_context_reg(CONTEXT* ctx, unsigned regno, unsigned* size)
 {
-    FIXME("not done for ARM\n");
+#ifdef __arm__
+    switch (regno)
+    {
+    case CV_ARM_R0 +  0: *size = sizeof(ctx->R0); return &ctx->R0;
+    case CV_ARM_R0 +  1: *size = sizeof(ctx->R1); return &ctx->R1;
+    case CV_ARM_R0 +  2: *size = sizeof(ctx->R2); return &ctx->R2;
+    case CV_ARM_R0 +  3: *size = sizeof(ctx->R3); return &ctx->R3;
+    case CV_ARM_R0 +  4: *size = sizeof(ctx->R4); return &ctx->R4;
+    case CV_ARM_R0 +  5: *size = sizeof(ctx->R5); return &ctx->R5;
+    case CV_ARM_R0 +  6: *size = sizeof(ctx->R6); return &ctx->R6;
+    case CV_ARM_R0 +  7: *size = sizeof(ctx->R7); return &ctx->R7;
+    case CV_ARM_R0 +  8: *size = sizeof(ctx->R8); return &ctx->R8;
+    case CV_ARM_R0 +  9: *size = sizeof(ctx->R9); return &ctx->R9;
+    case CV_ARM_R0 + 10: *size = sizeof(ctx->R10); return &ctx->R10;
+    case CV_ARM_R0 + 11: *size = sizeof(ctx->Fp); return &ctx->Fp;
+    case CV_ARM_R0 + 12: *size = sizeof(ctx->Ip); return &ctx->Ip;
+
+    case CV_ARM_SP: *size = sizeof(ctx->Sp); return &ctx->Sp;
+    case CV_ARM_LR: *size = sizeof(ctx->Lr); return &ctx->Lr;
+    case CV_ARM_PC: *size = sizeof(ctx->Pc); return &ctx->Pc;
+    case CV_ARM_CPSR: *size = sizeof(ctx->Cpsr); return &ctx->Cpsr;
+    }
+#endif
+    FIXME("Unknown register %x\n", regno);
     return NULL;
 }