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XGA_DrawLineBresenham() does not properly sign extend values

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https://sourceforge.net/p/dosbox/patches/269/ patch by Tom B

Imported-from: https://svn.code.sf.net/p/dosbox/code-0/dosbox/trunk@3992
This commit is contained in:
Sjoerd van der Berg 2016-09-04 18:47:39 +00:00
parent 5e4b1c8284
commit 4c4f232473
1 changed files with 3 additions and 3 deletions
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6
src/hardware/vga_xga.cpp
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@ -352,11 +352,11 @@ void XGA_DrawLineBresenham(Bitu val) {
// Probably a lot easier way to do this, but this works.
dminor = (Bits)((Bit16s)xga.desty);
if(xga.desty&0x2000) dminor |= 0xffffe000;
if(xga.desty&0x2000) dminor |= ~0x1fff;
dminor >>= 1;
destxtmp=(Bits)((Bit16s)xga.destx);
if(xga.destx&0x2000) destxtmp |= 0xffffe000;
if(xga.destx&0x2000) destxtmp |= ~0x1fff;
dmajor = -(destxtmp - (dminor << 1)) >> 1;
@ -374,7 +374,7 @@ void XGA_DrawLineBresenham(Bitu val) {
sy = -1;
}
e = (Bits)((Bit16s)xga.ErrTerm);
if(xga.ErrTerm&0x2000) e |= 0xffffe000;
if(xga.ErrTerm&0x2000) e |= ~0x1fff;
xat = xga.curx;
yat = xga.cury;