polmon: simplified r command

polmon.cc

@@ -224,20 +224,66 @@ void Status(uint8_t status) {
                  : "ax", "bh", "dx", "cx", "di", "cc");
 }
 
+char toupper(char c) {
+    if (c >= 'a' && c <= 'z') {
+        return c - ('a' - 'A');
+    }
+    return c;
+}
+
+void tofatname(const char* name, char* fatname) {
+    for (int i = 0; i < 11; i++) {
+        if (*name == 0 || *name == '.') {
+            fatname[i] = ' ';
+        } else {
+            fatname[i] = toupper(*name++);
+        }
+        if (i == 7 && *name == '.') {
+            name++;
+        }
+    }
+}
+
 void LaunchFile(const char* name) {
     constexpr uint16_t kSegment = 0x200;
     constexpr uint16_t kAddress = 0x100;
+    constexpr uint16_t kHeaderAddress = (kSegment << 4);
     constexpr uint16_t kFlatAddress = (kSegment << 4) + kAddress;
+    constexpr uint8_t kTrampoline[] = { 0xe8, 0xfd, 0x00, 0xcb };
 
-    asm volatile("mov %1, %%ax       \n\t"
+    char fatname[11];
-                 "push %%ax          \n\t"
+    tofatname(name, fatname);
-                 "mov %0, %%ax       \n\t"
+
-                 "push %%ax          \n\t"
+    auto* ptr = reinterpret_cast<uint8_t*>(kHeaderAddress);
-                 "mov $04, %%ah      \n\t"
+    memcpy(ptr, kTrampoline, sizeof(kTrampoline));
-                 "int $0x80          \n\t"
+
-                 "ljmp %2,%3" ::"rmi"(name),
+    asm volatile("mov %1, %%ax      \n\t"
-                 "rmi"(kFlatAddress), "i"(kSegment), "i"(kAddress)
+                 "push %%ax         \n\t"
-                 : "ax", "memory");
+                 "mov %0, %%ax      \n\t"
+                 "push %%ax         \n\t"
+                 "mov $04, %%ah     \n\t"
+                 "int $0x80         \n\t"
+                 "add $4, %%sp      \n\t"
+                 "mov %2, %%ax      \n\t"
+                 "mov %%ax, %%ds    \n\t"
+                 "mov %%ax, %%es    \n\t"
+                 "cli               \n\t"
+                 "mov %%ax, %%ss    \n\t"
+                 "mov %3, %%ax      \n\t"
+                 "xchg %%ax, %%sp   \n\t"
+                 "sti               \n\t"
+                 "push %%ax         \n\t"
+                 "lcall %2,$0       \n\t"
+                 "xor %%ax, %%ax    \n\t"
+                 "mov %%ax, %%ds    \n\t"
+                 "mov %%ax, %%es    \n\t"
+                 "cli               \n\t"
+                 "pop %%sp          \n\t"
+                 "mov %%ax, %%ss    \n\t"
+                 "sti"
+                 :: "rmi"(fatname),
+                 "rmi"(kFlatAddress), "i"(kSegment), "i"(kHeaderAddress)
+                 : "ax", "bx", "cx", "dx", "memory");
 }
 
 #if CTRLBREAK
@@ -320,12 +366,13 @@ bool ParseCommand(const char* buf, uint16_t& cur_addr, uint16_t& cur_seg) {
         } else if (*ptr == 'r') {
             dump = false;
             ptr++;
+            while (*ptr == ' ') {
+                ptr++;
+            }
             int l = 0;
             for (; ptr[l]; l++) {
             }
-            if (l >= 11) {
+            LaunchFile(ptr);
-                LaunchFile(ptr);
-            }
             ptr += l;
 #endif  // LAUNCH
         } else if (*ptr == 'w') {
@@ -364,7 +411,7 @@ void polmon() {
 
     ClearScreen();
 #if SHOWTITLE
-    puts("PolMon 0.2\r\n");
+    puts("PolMon for Workgroups 3.1\r\n");
 #endif  // SHOWTITLE
     DisplayPrompt();