The DEVICECONTEXT structure is a device-dependent structure internal to grabbers. Its layout, content, and length will vary from grabber to grabber.
The following is the DEVICECONTEXT structure for the grabbers for Hercules adapters:
DeviceContext struc
dcScrMode db ? ;BIOS screen mode
dcScrStart dw ? ;regeneration of start position
dcCursorPosn dw ? ;cursor position in CRTC format
dcCursorMode dw ? ;cursor start/stop scan lines
dcModeCtl db ? ;3x8 mode register data
dcExModeCtl db ? ;3xx extended-mode register data
dcColorSelect db ? ;3D9 color select register data
dcCrtcParms dw? ;-> CRTC parameters for non-BIOS modes
dcfSwitchGmt db ? ;switch graphics/multiple text
DeviceContext ends
The following is the DEVICECONTEXT structure for EGA grabbers:
DeviceContext struc
dcScrMode db ? ;BIOS screen mode
dcScrStart dw ? ;regeneration of start position
dcCursorPosn dw ? ;cursor position in CRTC format
dcCursorMode dw ? ;cursor start/stop scan lines
dcAddrPatch db ? ;3Dx / 3Bx patch byte
dcfSwitchGmt db ? ;switch graphics/multiple text
dcFileNum dw ? ;-> random number in swap file
dcFontBank db 4 dup (?) ;ERI font information
dcSwapPath db 64 dup (?) ;full swap path
DeviceContext ends
The following is the DEVICECONTEXT structure for VGA grabbers:
DeviceContext struc
dcScrMode db ? ;BIOS screen mode
dcScrStart dw ? ;regeneration of start position
dcCursorPosn dw ? ;cursor position in CRTC format
dcCursorMode dw ? ;cursor start/stop scan lines
dcAddrPatch db ? ;3Dx / 3Bx patch byte
dcfSwitchGmt db ? ;switch graphics/multiple text
dcFileNum dw ? ;-> random number in swap file
dcFontBank db 8 dup (?) ;VGA has 8 font banks
dcSwapPath db 64 dup (?) ;full swap path
DeviceContext ends