polmon: add r command

polmon.cc

@@ -12,6 +12,7 @@
 #define INT80H 0
 #define SHOWTITLE 0
 #define BOOTSTRAP 0
+#define LAUNCH 0
 #endif  // WOZMON
 
 #ifndef BACKSPACE
@@ -38,6 +39,10 @@
 #define BOOTSTRAP 1
 #endif
 
+#ifndef LAUNCH
+#define LAUNCH 1
+#endif
+
 namespace {
 
 #if WOZMON
@@ -213,6 +218,22 @@ void Status(uint8_t status) {
                  : "ax", "bh", "dx", "cx", "di", "cc");
 }
 
+void LaunchFile(const char* name) {
+    constexpr uint16_t kSegment = 0x200;
+    constexpr uint16_t kAddress = 0x100;
+    constexpr uint16_t kFlatAddress = (kSegment << 4) + kAddress;
+
+    asm volatile("mov %1, %%ax       \n\t"
+                 "push %%ax          \n\t"
+                 "mov %0, %%ax       \n\t"
+                 "push %%ax          \n\t"
+                 "mov $04, %%ah      \n\t"
+                 "int $0x80          \n\t"
+                 "ljmp %2,%3" ::"rmi"(name),
+                 "rmi"(kFlatAddress), "i"(kSegment), "i"(kAddress)
+                 : "ax", "memory");
+}
+
 bool ParseCommand(const char* buf, uint16_t& cur_addr, uint16_t& cur_seg) {
     bool dump = true;
     for (const char* ptr = buf; *ptr;) {
@@ -259,7 +280,19 @@ bool ParseCommand(const char* buf, uint16_t& cur_addr, uint16_t& cur_seg) {
             dump = false;
             ClearScreen();
             ptr++;
-#endif
+#endif  // CLEARSCREENCMD
+#if LAUNCH
+        } else if (*ptr == 'r') {
+            dump = false;
+            ptr++;
+            int l = 0;
+            for (; ptr[l]; l++) {
+            }
+            if (l >= 11) {
+                LaunchFile(ptr);
+            }
+            ptr += l;
+#endif  // LAUNCH
         } else if (*ptr == 'w') {
             dump = false;
             uint16_t addr = cur_addr;