ChorusOS 5.0 Board Support Package Developer's Guide

Banks

The bankDesc structure points to an array of BankDesc system image memory bank descriptors.

typedef struct BankDesc {     
        char*    id;      /* bank's symbolic name */ 
        BankType type;    /* bank's type */ 
        char*    fs;      /* files system type symbolic name */
        VmAddr   vaddr;   /* address required for the bank's image */
        VmSize   size;    /* bank's size */ 
} BankDesc;

The bankDesc structure is declared in source_dir/nucleus/sys/common/src/kern/bki/bki.h. A memory bank is specified by vaddr, indicating the starting address within the initial address space, and size.

The type field value is a combination of the bits listed in Table 7-1.

Table 7-1 type Bits


`type` Bit	Meaning
`BANK_KSP`	always "1" in this version
`BANK_DEVICE`	bank is a memory device
`BANK_DEVICE_READ`	data from the memory device can be read
`BANK_DEVICE_WRITE`	data from the memory device can be modified
`BANK_DEVICE_EXEC`	instructions from the memory device can be executed

If any of the last three bits is set, the BANK_DEVICE bit must also be set.

Files in a memory bank can be organized as a volume of a file system. In this case, the fs field points to a string containing the name of the file system type (for example, "FAT" stands for MS-DOS FAT file system). Otherwise, fs is 0.

When the initial loader jumps to the bootconf entry point, the memory banks containing the BIN_BOOTCONF and BIN_BOOTSTRAP program binaries must already be installed at the address indicated by vaddr.

When the bootstrap program transfers control to the microkernel, all memory banks must be installed at the address indicated by vaddr.