Add more low-level API function to load the kernel, and make the

menu subsystem use it.

2 files changed, 46 insertions, 8 deletions

diff --git a/com32/include/com32.h b/com32/include/com32.h
index 29656e47..5706683c 100644
--- a/com32/include/com32.h
+++ b/com32/include/com32.h
@@ -88,18 +88,35 @@ void __farcall(uint16_t __es, uint16_t __eo,
  * 0..0xFFFFF and real-mode style SEG:OFFS pointers.  Note that a
  * 32-bit linear pointer is not compatible with a SEG:OFFS pointer
  * stored in two consecutive 16-bit words.
+ *
+ * Use OFFS_WRT() if you want to compute an offset relative to a
+ * specific segment.  OFFS_VALID() will return whether or not the
+ * pointer is actually reachable from the target segment.
  */
-static inline uint16_t SEG(void *__p)
+static inline uint16_t SEG(const volatile void *__p)
 {
   return (uint16_t)(((uintptr_t)__p) >> 4);
 }
 
-static inline uint16_t OFFS(void *__p)
+static inline uint16_t OFFS(const volatile void *__p)
 {
   /* The double cast here is to shut up gcc */
   return (uint16_t)(uintptr_t)__p & 0x000F;
 }
 
+static inline uint16_t OFFS_WRT(const volatile void *__p, uint16_t seg)
+{
+  return (uint16_t)((uintptr_t)__p - ((uintptr_t)seg << 4));
+}
+
+static inline int OFFS_VALID(const volatile void *__p, uint16_t seg)
+{
+  uintptr_t __segstart = (uintptr_t)seg << 4;
+  uintptr_t __ptr = (uintptr_t)__p;
+
+  return (__ptr >= __segstart) && (__ptr <= __segstart+0xffff);
+}
+
 static inline void *MK_PTR(uint16_t __seg, uint16_t __offs)
 {
   return (void *)((__seg << 4) + __offs);
diff --git a/com32/modules/menu.c b/com32/modules/menu.c
index 85ff8d5a..d67f5b55 100644
--- a/com32/modules/menu.c
+++ b/com32/modules/menu.c
@@ -588,10 +588,11 @@ run_menu(void)
 
 
 static void
-execute(const char *cmdline)
+execute(char *cmdline)
 {
 #ifdef __COM32__
-  static com32sys_t ireg;
+  com32sys_t ireg;
+  memset(&ireg, 0, sizeof ireg);
 
   if ( !strncmp(cmdline, ".localboot", 10) && isspace(cmdline[10]) ) {
     unsigned long localboot = strtoul(cmdline+10, NULL, 0);
@@ -599,10 +600,30 @@ execute(const char *cmdline)
     ireg.eax.w[0] = 0x0014;	/* Local boot */
     ireg.edx.w[0] = localboot;
   } else {
-    strcpy(__com32.cs_bounce, cmdline);
-    ireg.eax.w[0] = 0x0003;	/* Run command */
-    ireg.ebx.w[0] = OFFS(__com32.cs_bounce);
-    ireg.es = SEG(__com32.cs_bounce);
+    const char *p;
+    char *q = __com32.cs_bounce;
+    const char *kernel, *args;
+
+    kernel = q;
+    p = cmdline;
+    while ( *p && !isspace(*p) ) {
+      *p++ = *q++;
+    }
+    *q++ = '\0';
+
+    args = q;
+    while ( *p && isspace(*p) )
+      p++;
+      
+    strcpy(q, p);
+
+    ireg.eax.w[0] = 0x0016;
+    ireg.esi.w[0] = OFFS(kernel);
+    ireg.ds       = SEG(kernel);
+    ireg.ebx.w[0] = OFFS(args);
+    ireg.es       = SEG(kernel);
+    /* ireg.ecx.l    = 0; */		/* We do ipappend "manually" */
+    /* ireg.edx.l    = 0; */
   }
 
   __intcall(0x22, &ireg, NULL);