## Display Device Driver Reference for OS/2

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### Strategy 1 - Change the Shadow8514Regs

Retain the pixmaps and other characteristics of the XGA driver and change the 8514 registers to match the new driver. This is the approach that was taken when the 8514/A driver was ported from the original XGA-code base. This is the most efficient solution, because the values from the new renamed driver can be written directly to the hardware. The tradeoff here is that the bit-map drawing code in EDDFFAST.ASM, FFLINES.ASM, FFBLTSET.ASM , and so forth, use the shadow registers extensively; therefore, modifying them will be a significant portion of the work. The other tradeoff is that functions such as eddn_BitBlt and PixBltThroughClipsViaPhunk make extensive use of these registers, and changing them may mean making significant changes to the logic of these complex functions.