The boot code supports API calls to display characters and strings. Application programs can inquire the location of the video RAM from the boot code for their own screen I/O. For example, function printf or object cout will use these functions. To accomplish this, RTTarget-32's boot code must know where the video RAM (if any) is located. The syntax for the VideoRAM command is:

VideoRAM = RegionName | None

where parameter RegionName must have been defined in a previous Region command. The video RAM is assumed to be located in the given region. If None is specified, the boot code will assume that no display adapter is installed and program output will be sent to the port specified with the COMPort command.

If an application is booted with boot code Biosboot.exe and the configuration file does not contain a VideoRAM = None command, the boot code will enquire the location of the video RAM from the BIOS at startup, overriding whatever value was specified in the configuration file. This allows the same program configuration to run on targets with color or monochrome displays. However, this feature only works if both video RAM areas at B0000h and B8000h have ReadWrite access permission.

The default value for the VideoRAM is None.

Left Defining Boot Code Options

BOOTFLAGS Command

Down GMode Command