Normal quotes

44-06.md

@@ -4,28 +4,28 @@
 
 #### Knowing When to Flip {#Heading8 align="center"}
 
-There’s a hitch, though, and that hitch is knowing exactly when it is
-that the page has flipped. The page doesn’t flip the instant that you
+There's a hitch, though, and that hitch is knowing exactly when it is
+that the page has flipped. The page doesn't flip the instant that you
 set the Start Address registers. The VGA loads the starting offset from
 the Start Address registers once before starting each frame, then pays
 those registers no nevermind until the next frame comes around. This
 means that you can set the Start Address registers whenever you want—but
-the page actually being displayed doesn’t change until after the VGA
+the page actually being displayed doesn't change until after the VGA
 loads that new offset in preparation for the next frame.
 
 The potential problem should be obvious. Suppose that page 1 is being
-displayed, and you’re updating page 0. You finish drawing to page 0, set
+displayed, and you're updating page 0. You finish drawing to page 0, set
 the Start Address registers to 0 to switch to displaying page 0, and
 start updating page 1, which is no longer displayed. Or is it? If the
 VGA was in the middle of the current frame, displaying page 1, when you
 set the Start Address registers, then page 1 is going to be displayed
 for the rest of the frame, no matter what you do with the Start Address
 registers. If you start updating page 1 right away, any changes you make
-may well show up on the screen, because page 0 hasn’t yet flipped to
+may well show up on the screen, because page 0 hasn't yet flipped to
 being displayed in place of page 1—and that defeats the whole purpose of
 page flipping.
 
-To avoid this problem, it is mandatory that you wait until you’re sure
+To avoid this problem, it is mandatory that you wait until you're sure
 the page has flipped. The Start Address registers are, according to my
 tests, loaded at the start of the Vertical Sync signal, although that
 may not be the case with all VGA clones. The Vertical Sync status is
@@ -42,14 +42,14 @@ Start Address High value for one page would be mixed with the Start
 Address Low value for the other page, and, depending on the start
 address values, the whole screen could appear to shift any number of
 pixels for a single, horrible frame. *This must never happen!* The
-solution is to set the Start Address registers when you’re certain
+solution is to set the Start Address registers when you're certain
 Vertical Sync is not about to start. The easiest way to know that is to
 check for the Display Enable status (bit 0 of the Input Status 1
 register) being active; that means that bitmap-controlled pixels are
 being scanned onto the screen, and, since Vertical Sync happens in the
 middle of the vertical non-display portion of the frame, Vertical Sync
 can never be anywhere nearby if Display Enable is active. (Note that one
-good alternative is to set up both pages with a start address that’s a
+good alternative is to set up both pages with a start address that's a
 multiple of 256, and just change the Start Address High register and
 wait for Vertical Sync, with no Display Enable wait required.)
 
@@ -69,20 +69,20 @@ farther each time and the like) if updates are happening too slowly.
 
 #### Enter the Split Screen {#Heading9}
 
-So far, I’ve discussed page flipping in 640x350 mode. There’s a reason
+So far, I've discussed page flipping in 640x350 mode. There's a reason
 for that: 640x350 is the highest-resolution standard mode in which
-there’s enough display memory for two full pages on a standard VGA. It’s
+there's enough display memory for two full pages on a standard VGA. It's
 possible to program the VGA to a non-standard 640x400 mode and still
-have two full pages, but that’s pretty much the limit. One 640x480 page
-takes 38,400 bytes of display memory, and clearly there isn’t enough
+have two full pages, but that's pretty much the limit. One 640x480 page
+takes 38,400 bytes of display memory, and clearly there isn't enough
 room in 64 K of display memory for two of *those* monster pages.
 
 And yet, 640x480 is a wonderful mode in many ways. It offers a 1:1
 aspect ratio (square pixels), and it provides by far the best resolution
-of any 16-color mode. Surely there’s *some* way to bring the visual
+of any 16-color mode. Surely there's *some* way to bring the visual
 appeal of page flipping to this mode?
 
-Surely there is—but it’s an odd solution indeed. The VGA has a feature,
+Surely there is—but it's an odd solution indeed. The VGA has a feature,
 known as the *split screen,* that allows you to force the offset from
 which the VGA fetches video data back to 0 after any desired scan line.
 For example, you can program the VGA to scan through display memory as
@@ -119,12 +119,12 @@ flipping gives you the best combination of square pixels and high
 resolution possible on a standard VGA.
 
 So. Is VGA animation worth all the fuss? *Mais oui.* Run the sample
-program; if you’ve never seen aggressive VGA animation before, you’ll be
+program; if you've never seen aggressive VGA animation before, you'll be
 amazed at how smooth it can be. Not every square millimeter of every
 animated screen must be in constant motion. Most graphics screens need a
 little quiet space to display scores, coordinates, file names, or (if
-all else fails) company logos. If you don’t tell the user he’s/she’s
-only getting 339 scan lines of animation, he’ll/she’ll probably never
+all else fails) company logos. If you don't tell the user he's/she's
+only getting 339 scan lines of animation, he'll/she'll probably never
 know.
 
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