feature: doublebuffer quickflip added

Author: msaarna

includes/std_routines.asm

@@ -2306,10 +2306,6 @@ flipdisplaybuffer
 
          jsr terminatedisplaybuffer ; terminate the working buffer before we flip
 
-         lda doublebufferstate
-         lsr ; /2, so we'll see 0 or 1, rather than 1 or 3
-         tax
-
          ; ensure we don't flip mid-display. otherwise the displayed DL will be the one the game is working on.
 
 flipdisplaybufferwait1
@@ -2320,6 +2316,11 @@ flipdisplaybufferwait
          lda visibleover
          bne flipdisplaybufferwait
 
+quickbufferflip
+         lda doublebufferstate
+         lsr ; /2, so we'll see 0 or 1, rather than 1 or 3
+         tax
+
          lda doublebufferminimumframetarget
          beq skipminimumframecode
          lda doublebufferminimumframeindex

statements.c

@@ -10686,8 +10686,8 @@ void adjustvisible (char **statement)
 
 void doublebuffer (char **statement)
 {
-    //  1              2            3
-    // doublebuffer [on/off/flip] [minimumframe]
+    //  1              2                         3
+    // doublebuffer [on/off/flip/quickflip] [minimumframe]
     assertminimumargs (statement, "adjustvisible", 1);
 
     // enable the compile-time optional code
@@ -10714,6 +10714,10 @@ void doublebuffer (char **statement)
     {
 	printf ("  jsr flipdisplaybuffer\n");
     }
+    else if (strcmp (statement[2], "quickflip") == 0)
+    {
+	printf ("  jsr quickbufferflip\n");
+    }
     else
     {
 	prerror ("doublebuffer argument needs to be 'on' or 'off'");