Normal quotes

58-02.md

@@ -5,20 +5,20 @@
 **LISTING 58.1 L58-1.ASM**
 
     ; Inner loop to draw a single texture-mapped horizontal scanline in
-    ; Mode X, the VGA’s page-flipped 256-color mode. Because adjacent
+    ; Mode X, the VGA's page-flipped 256-color mode. Because adjacent
     ; pixels lie in different planes in Mode X, an OUT must be performed
     ; to select the proper plane before drawing each pixel.
     ;
     ; At this point:
-    ;       AL = initial pixel’s plane mask
+    ;       AL = initial pixel's plane mask
     ;       DS:BX = initial source texture pointer
-    ;       DX = pointer to VGA’s Sequencer Data register
+    ;       DX = pointer to VGA's Sequencer Data register
     ;       SI = # of pixels to fill
     ;       ES:DI = pointer to initial destination pixel
 
     TexScanLoop:
 
-    ; Set the Map Mask for this pixel’s plane, then draw the pixel.
+    ; Set the Map Mask for this pixel's plane, then draw the pixel.
 
             out     dx,al
             mov     ah,[bx]         ;get texture pixel
@@ -29,14 +29,14 @@
             add     bx,[bp].lXBaseAdvance     ;advance the minimum # of pixels in X
             mov     cx,word ptr [bp].lSourceStepX
             add     word ptr [bp].lSourceX,cx ;step the source X fractional part
-            jnc     NoExtraXAdvance           ;didn’t turn over; no extra advance
+            jnc     NoExtraXAdvance           ;didn't turn over; no extra advance
             add     bx,[bp].lXAdvanceByOne    ;did turn over; advance X one extra
     NoExtraXAdvance:
 
             add     bx,[bp].lYBaseAdvance     ;advance the minimum # of pixels in Y
             mov     cx,word ptr [bp].lSourceStepY
             add     word ptr [bp].lSourceY,cx ;step the source Y fractional part
-            jnc     NoExtraYAdvance           ;didn’t turn over; no extra advance
+            jnc     NoExtraYAdvance           ;didn't turn over; no extra advance
             add     bx,[bp].lYAdvanceByOne    ;did turn over; advance Y one extra
     NoExtraYAdvance:
 
@@ -54,11 +54,11 @@
 Figure 58.2 shows why this cycling is necessary. In Mode X, the
 page-flipped 256-color mode of the VGA, each successive pixel across a
 scanline is stored in a different hardware plane, and an **OUT** to the
-VGA’s hardware is needed to select the plane being drawn to. (See
+VGA's hardware is needed to select the plane being drawn to. (See
 Chapters 47, 48, and 49 for details.) An **OUT** instruction *by itself*
 takes 16 cycles (and in the neighborhood of 30 cycles in virtual-86 or
 non-privileged protected mode), and an **ROL** takes 2 more, for a total
-of 18 cycles, double John’s 9 cycles, just to handle plane management.
+of 18 cycles, double John's 9 cycles, just to handle plane management.
 Clearly, getting plane control out of the inner loop was absolutely
 necessary.
 
@@ -68,7 +68,7 @@ necessary.
 I must confess, with some embarrassment, that at this point I threw
 myself into designing a solution that involved executing the texture
 mapping code up to four times per scanline, once for the pixels in each
-plane. It’s hard to overstate the complexity of this approach, which
+plane. It's hard to overstate the complexity of this approach, which
 involves quadrupling the normal pixel-to-pixel increments, adjusting the
 start value for each of the passes, and dealing with some nasty boundary
 cases. Make no mistake, the code was perfectly doable, and would in fact
@@ -76,29 +76,29 @@ have gotten plane control out of the inner loop, but would have been
 very difficult to get exactly right, and would have suffered from
 substantial overhead.
 
-Fortunately, in the last sentence I was able to say “would have,” not
-“was,” because my friend Chris Hecker (checker@bix.com) came along to
+Fortunately, in the last sentence I was able to say "would have," not
+"was," because my friend Chris Hecker (checker@bix.com) came along to
 toss a figurative bucket of cold water on my right brain, which was
 evidently asleep. (Or possibly stolen by scantily-clad, attractive
-aliens; remember “Spock’s Brain”?) Chris is the author of the WinG
+aliens; remember "Spock's Brain"?) Chris is the author of the WinG
 Windows game graphics package, available from Microsoft via FTP,
 CompuServe, or MSDN Level 2; if, like me, you were at the Game
 Developers Conference in April 1994, you, along with everyone else, were
-stunned to see Id’s megahit DOOM running at full speed in a window,
-thanks to WinG. If you write games for a living, run, don’t walk, to
+stunned to see Id's megahit DOOM running at full speed in a window,
+thanks to WinG. If you write games for a living, run, don't walk, to
 check WinG out!
 
 Chris listened to my proposed design for all of maybe 30 seconds,
-growing visibly more horrified by the moment, before he said, “But why
-don’t you just draw vertical rather than horizontal scanlines?”
+growing visibly more horrified by the moment, before he said, "But why
+don't you just draw vertical rather than horizontal scanlines?"
 
 Why indeed?
 
 #### A 90-Degree Shift in Perspective {#Heading5}
 
 As I said earlier, how you look at an optimization problem defines how
-you’ll be able to solve it. In order to boost performance, sometimes
-it’s necessary to look at things from a different angle—and for texture
+you'll be able to solve it. In order to boost performance, sometimes
+it's necessary to look at things from a different angle—and for texture
 mapping this was literally as well as figuratively true. Chris suggested
 nothing more nor less than scanning out polygons at a 90-degree angle to
 normal, starting, say, at the left edge of the polygon, and
@@ -108,10 +108,10 @@ would be in the same plane, and I would need to change planes only
 between columns—outside the inner loop. A trivial change, not
 fundamental in any sense—and yet just that one change, plus unrolling
 the loop, reduced the inner loop to the 22-cycles-per-pixel version
-shown in Listing 58.2. That’s exactly twice as fast as Listing 58.1—and
+shown in Listing 58.2. That's exactly twice as fast as Listing 58.1—and
 given how incredibly slow most VGAs are at completing **OUT**s, the
 real-world speedup should be considerably greater still. (The fastest
-byte **OUT** I’ve ever measured for a VGA is 29 cycles, the slowest more
+byte **OUT** I've ever measured for a VGA is 29 cycles, the slowest more
 than 60 cycles; in the latter case, Listing 58.2 would be on the order
 of *four* times faster than Listing 58.1.)
 
@@ -132,7 +132,7 @@ of *four* times faster than Listing 58.1.)
 
          REPTLOOP_UNROLL
 
-    ; Set the Map Mask for this pixel’s plane, then draw the pixel.
+    ; Set the Map Mask for this pixel's plane, then draw the pixel.
 
             mov     ah,[bx]         ;get texture pixel
             mov     es:[di],ah      ;set screen pixel
@@ -142,14 +142,14 @@ of *four* times faster than Listing 58.1.)
             add     bx,[bp].lXBaseAdvance     ;advance the minimum # of pixels in X
             mov     cx,word ptr [bp].lSourceStepX
             add     word ptr [bp].lSourceX,cx ;step the source X fractional part
-            jnc     NoExtraXAdvance           ;didn’t turn over; no extra advance
+            jnc     NoExtraXAdvance           ;didn't turn over; no extra advance
             add     bx,[bp].lXAdvanceByOne    ;did turn over; advance X one extra
     NoExtraXAdvance:
 
             add     bx,[bp].lYBaseAdvance     ;advance the minimum # of pixels in Y
             mov     cx,word ptr [bp].lSourceStepY
             add     word ptr [bp].lSourceY,cx ;step the source Y fractional part
-            jnc     NoExtraYAdvance           ;didn’t turn over; no extra advance
+            jnc     NoExtraYAdvance           ;didn't turn over; no extra advance
             add     bx,[bp].lYAdvanceByOne    ;did turn over; advance Y one extra
     NoExtraYAdvance: