vga_io.bas

Contains IO primitives for VGA based displays, as well as some mode setters.

Author

Marcel Sondaar

License

Public Domain

Summary

vga_io.bas	Contains IO primitives for VGA based displays, as well as some mode setters.
Functions
Write3C0	Writes an index/value pair to VGA register 3C0 (Attribute Control Register)
Write3C2	Writes to VGA register 3C2 (Miscellaneous Output Register)
Write3C4	Writes an index/value pair to VGA register 3C4 (Sequencer Register)
Write3C6	Writes to VGA register 3C6 (DAC Mask Register)
Write3CE	Writes an index/value pair to VGA register 3CE (Graphics Controller Register)
Write3D4	Writes an index/value pair to VGA register 3D4 (CRTC Controller)
Read3C0	Reads an value from the indexed VGA register 3C0 (Attribute Control Register)
Read3C2	Reads the value from VGA register 3C2 (Miscellaneous Output Register)
Read3C4	Reads an value from the indexed VGA register 3C4 (Sequencer Register)
Read3C6	Reads the value from VGA register 3C6 (DAC Mask)
Read3CE	Reads an value from the indexed VGA register 3CE (Graphics Controller Register)
Read3D4	Reads an value from the indexed VGA register 3D4 (CRTC Register)
VGAUnlockCRTC	unlocks the CRTC registers
VGAEnableDisplay	Enables video output on the VGA
VGASet320x200Mode	Set the VGA registers to a 320x200 Mode
VGASet320x240Mode	Set the VGA registers to a 320x240 Mode
VGASet400x300Mode	Set the VGA registers to a 400x300 Mode
VGASet640x480x16Mode	Set the VGA registers to 640x480 16 colors
VGASetTextMode	Set the VGA registers to standard text mode
VGASetModeX	Modifies the CRTC and Sequencer to enter planar addressing mode from a linear mode

Functions

Write3C0

Sub Write3C0 Cdecl Alias "Write3C0" ( index as byte,
value as Unsigned byte )

Writes an index/value pair to VGA register 3C0 (Attribute Control Register)

in

index	the AC register to access
value	the value to write

Write3C2

Sub Write3C2 Cdecl Alias "Write3C2" ( value as Unsigned byte )

Writes to VGA register 3C2 (Miscellaneous Output Register)

in

value

the value to write

Write3C4

Sub Write3C4 Cdecl Alias "Write3C4" ( index as byte,
value as Unsigned byte )

Writes an index/value pair to VGA register 3C4 (Sequencer Register)

in

index	the Sequencer register to access
value	the value to write

Write3C6

Sub Write3C6 Cdecl Alias "Write3C6" ( value as Unsigned byte )

Writes to VGA register 3C6 (DAC Mask Register)

in

value

the value to write

Write3CE

Sub Write3CE Cdecl Alias "Write3CE" ( index as byte,
value as Unsigned byte )

Writes an index/value pair to VGA register 3CE (Graphics Controller Register)

in

index	the Graphics Register to access
value	the value to write

Write3D4

Sub Write3D4 Cdecl Alias "Write3D4"( index as byte,
value as Unsigned byte )

Writes an index/value pair to VGA register 3D4 (CRTC Controller)

in

index	the CRTC register to access
value	the value to write

Read3C0

Function Read3C0 Cdecl Alias "Read3C0" ( index As Byte ) As Unsigned Byte

Reads an value from the indexed VGA register 3C0 (Attribute Control Register)

in

index

the AC register to access

out

return

the value of the register

Read3C2

Function Read3C2 Cdecl Alias "Read3C2" () As Unsigned Byte

Reads the value from VGA register 3C2 (Miscellaneous Output Register)

out

return

the value of the Miscellaneous Output Register

Read3C4

Function Read3C4 Cdecl Alias "Read3C4" ( index As Byte ) As Unsigned Byte

Reads an value from the indexed VGA register 3C4 (Sequencer Register)

in

index

the Sequencer register to access

out

return

the value of the register

Read3C6

Function Read3C6 Cdecl Alias "Read3C6" As Unsigned Byte

Reads the value from VGA register 3C6 (DAC Mask)

out

return

the value of the DAC Mask Register

Read3CE

Function Read3CE Cdecl Alias "Read3CE" ( index As Byte ) As Unsigned Byte

Reads an value from the indexed VGA register 3CE (Graphics Controller Register)

in

index

the GC register to access

out

return

the value of the register

Read3D4

Function Read3D4 Cdecl Alias "Read3D4" ( index As Byte ) As Unsigned Byte

Reads an value from the indexed VGA register 3D4 (CRTC Register)

in

index

the CRTC register to access

out

return

the value of the register

VGAUnlockCRTC

Sub VGAUnlockCRTC Cdecl Alias "VGAUnlockCRTC" ()

unlocks the CRTC registers

VGAEnableDisplay

Sub VGAEnableDisplay Cdecl Alias "VGAEnableDisplay" ()

Enables video output on the VGA

VGASet320x200Mode

Sub VGASet320x200Mode Cdecl Alias "VGASet320x200Mode" ()

Set the VGA registers to a 320x200 Mode

VGASet320x240Mode

Sub VGASet320x240Mode Cdecl Alias "VGASet320x240Mode"()

Set the VGA registers to a 320x240 Mode

VGASet400x300Mode

Sub VGASet400x300Mode Cdecl Alias "VGASet400x300Mode"()

Set the VGA registers to a 400x300 Mode

VGASet640x480x16Mode

Sub VGASet640x480x16Mode Cdecl Alias "VGASet640x480x16Mode"()

Set the VGA registers to 640x480 16 colors

VGASetTextMode

Sub VGASetTextMode Cdecl Alias "VGASetTextMode" ()

Set the VGA registers to standard text mode

VGASetModeX

Sub VGASetModeX Cdecl Alias "VGASetModeX"()

Modifies the CRTC and Sequencer to enter planar addressing mode from a linear mode

To avoid confusion, some only consider “Mode X” to be unchained 320x240x8, but in general it can apply to any 256-color mode