SuperHires mode provides a 35ns pixel display rate - twice the horizontal resolution of Hires mode, and four times the Lores rates. The nominal resolution of a SuperHires viewport is 1280 pixels. The maximum plane depth for a SuperHires viewport is 2 bitplanes which saturates DMA bandwidth as much as four Hires bitplanes. This mode is controlled by the graphics.library by writing to the BPLCON0 register in the LOF copperlist (/SHF if interlaced). BPLCON0 chg W A,D Bitplane control register (misc control bits) Bit Use --- --- 15 HIRES Set it to zero if SHRES enabled 14 BPU2 \ 13 BPU1 } Depth of SuperHires mode (1 or 2) 12 BPU0 / 11 HAM Incompatible w/ SuperHires mode 10 DPF Compatible with SuperHires mode 09 08 07 06 SHRES SuperHires 35ns pixel enable bit 05 BPLHWRM 04 SPRHWRM 03 LPEN Compatible with SuperHires mode 02 LACE Compatible with SuperHires mode 01 00 Warning: -------- Programmers must not rely on interpreting ViewPort->Modes bits directly when determining the mode of a ViewPort. Beginning with the V36 graphics.library, the ViewPort->Modes field is used for backward compatibility only. Under V1.3 and earlier the ViewPort->Modes field mirrored some of the BPLCON0 bits most notably Hires and Lace. However, other logical defines in this field such as the Viewport->Modes PF2PRI bit conflict with the SHRES bit assignment in the actual hardware. For this reason, in release 2.0 of the operating system (graphics.library V36 and later), programmers will need to use the new DataBase/ModeID scheme to determine their ViewPort's mode, and to specify a mode when creating, cloning, or copying ViewPorts.
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