1 files changed, 93 insertions, 0 deletions
diff --git a/bootblocks/help.c b/bootblocks/help.c
new file mode 100644
index 0000000..5083fdc
--- /dev/null
+++ b/bootblocks/help.c
@@ -0,0 +1,93 @@
+
+/*
+ * Display a page from help.txt, the argument is the scan code of a function
+ * key. F1..F10 display pages 1..10, HOME is page zero, PGUP and PGDN are
+ * previous and next page.
+ */
+
+#include <stdio.h>
+#include "readfs.h"
+
+struct keys {
+   int key;
+   int rel;
+   int abs;
+} keys[] = {
+   {0xC7, 0, 0},	/* HOME page 0*/
+   {0xBB, 0, 1},	/* F1   page 1 */
+   {0xBC, 0, 2},	/* F2   page 2 */
+   {0xBD, 0, 3},	/* F3   page 3 */
+   {0xBE, 0, 4},	/* F4   page 4 */
+   {0xBF, 0, 5},	/* F5   page 5 */
+   {0xC0, 0, 6},	/* F6   page 6 */
+   {0xC1, 0, 7},	/* F7   page 7 */
+   {0xC2, 0, 8},	/* F8   page 8 */
+   {0xC3, 0, 9},	/* F9   page 9 */
+   {0xC4, 0, 10},	/* F10  page 10 */
+
+   {0xC9, -1,0},	/* PGUP page-- */
+   {0xD1,  1,0},	/* PGDN page++ */
+
+   {0,0,1}
+};
+
+cmd_help(ptr)
+char * ptr;
+{
+static int lastpage = 0;
+   int helpkey = 1;
+   int i;
+
+   getnum(&ptr, &helpkey);
+
+   for(i=0; keys[i].key; i++)
+      if( keys[i].key == helpkey || i == helpkey )
+         break;
+
+   if( keys[i].key == 0 )
+   {
+      printf("Unbound key, press F1 for general help\n");
+      return -1;
+   }
+   
+   if( keys[i].rel ) lastpage += keys[i].rel;
+   else	             lastpage = keys[i].abs;
+
+   if( lastpage < 0 ) { lastpage=0; return 0; }
+
+   return display_help(lastpage);
+}
+
+display_help(page)
+int page;
+{
+   char buffer[1024];
+   long length= -1;
+   int left = 0;
+   int ch,lastch = '\n';
+   int flg = 0;
+
+   if( open_file("help.txt") < 0 )
+   {
+      if( page == 1 )
+         printf("Help file 'help.txt' is not available, sorry.\n");
+      return -1;
+   }
+
+   for(length = file_length(); length>0; length--)
+   {
+      if( left==0 )
+      {
+         if( read_block(buffer) < 0 ) break;
+	 left = 1024;
+      }
+      ch = buffer[1024-left]; left--;
+      if( ch == '%' && lastch == '\n' ) { flg = 1; page--; }
+      if( page < 0 ) break;
+      if( page == 0 && flg == 0 ) putchar(ch);
+      if( ch == '\n' ) flg = 0;
+      lastch = ch;
+   }
+   return 0;
+}
+