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Keil Software — A51/AX51/A251 Macro Assembler and Utilities

407

 

 

BANK_EX2 – Banking with Constants

This example shows how to place constants in code banks. You can use this

A

technique to place messages or large tables in code banks other than the one in

which your program resides. This example uses three source files: C_PROG.C,

 

C_MESS0.C, and C_MESS1.C.

 

You use the LX51 linker/locator to locate constant segments in particular code

 

banks. Segment names for constant data have the general format

 

?CO?modulename where modulename is the name of the source file the constant

 

data is declared.

 

 

In your C51 programs, when you access constant data that is in a different

 

segment, you must manually ensure that the proper code bank is used when

 

accessing that constant data. You so this with the switchbank function. This

 

function is defined in the L51_BANK.A51 source module.

 

Using C51 and BL51

 

These source files are compiled and linked using the following commands.

 

C51 C_PROG.C

DEBUG OBJECTEXTEND

 

C51 C_MESS0.C

DEBUG OBJECTEXTEND

 

C51 C_MESS1.C

DEBUG OBJECTEXTEND

 

BL51 C_PROG.OBJ, C_MESS0.OBJ, C_MESS1.OBJ

BANKAREA(8000H,0FFFFH) &

BANK0(?CO?C_MESS0 (8000H)) BANK1(?CO?C_MESS1 (8000H))

OC51 C_PROG

OH51 C_PROG.B00 HEXFILE (C_PROG.H00)

OH51 C_PROG.B01 HEXFILE (C_PROG.H01)

P_BANK2.OBJ

408 Appendix A. Application Examples

Using C51 and LX51

A

When you are using the extended LX51 linker/locater the program is generated

as shown below:

 

 

C51

C_PROG.C

DEBUG OMF251

 

C51

C_MESS0.C

DEBUG OMF251

 

C51

C_MESS1.C

DEBUG OMF251

LX51 C_PROG.OBJ, C_MESS0.OBJ, C_MESS1.OBJ

BANKAREA(8000H,0FFFFH) &

SEGMENTS (?CO?C_MESS0 (B0:8000H)) BANK1(?CO?C_MESS1 (B1:8000H))

OHX51 C_PROG

BANK_EX3 – Code Banking with PL/M-51

The following PL/M-51 example shows how to compile and link a PL/M-51 program using multiple code banks. The function of this example is similar to that shown in “BANK_EX1 – Code Banking with C51” on page 404.

The program begins with the procedure in P_ROOT.P51. This routine calls routines in other code banks, which, in turn, call routines in yet different code banks.

The PL/M-51 programs are compiled using the following commands.

PLM51 P_ROOT.P51 DEBUG

PLM51 P_BANK0.P51 DEBUG

PLM51 P_BANK1.P51 DEBUG

PLM51 P_BANK2.P51 DEBUG

In this example, P_ROOT.OBJ is located in the common area and P_BANK0.OBJ, P_BANK1.OBJ, and are located in the bank area.

NOTE

The PL/M-51 runtime library, PLM51.LIB, must be included in the linkage. You must either specify a path to the directory in which this library is stored, or you must include it directly in the linker command line.

Keil Software — A51/AX51/A251 Macro Assembler and Utilities

409

 

 

Using BL51

The BL51 linker/locator is invoked as follows:

BL51 COMMON{P_ROOT.OBJ}, BANK0{P_BANK0.OBJ}, & BANK1{P_BANK1.OBJ}, BANK2{P_BANK2.OBJ} & BANKAREA(8000H,0FFFFH)

A

The BANKAREA (8000H, 0FFFFH) control defines the address space 8000H to 0FFFFH as the area for code banks. The COMMON control places the P_ROOT.OBJ module in the common area. The BANK0, BANK1, and BANK2 controls place modules in bank 0, 1, and 2 respectively.

The BL51 linker/locator creates a listing file, P_ROOT.M51, which contains information about memory allocation and about the intra-bank jump table that is generated. BL51 also creates the output module, P_ROOT, which is stored in banked OMF format. You must use the OC51 banked object file converter to convert the banked OMF file into standard OMF files. OMF files may be loaded with the µVision2 Debugger/Simulator or an in-circuit emulator. Invoke the OC51 banked object file converter as follows:

OC51 P_ROOT

For this example program, the OC51 banked object file converter produces three standard OMF-51 files from P_ROOT. They are listed in the following table.

Filename Contents

P_ROOT.B00 All information (including symbols) for code bank 0 and the common area.

P_ROOT.B01 Information for code bank 1 and the common area.

P_ROOT.B02 Information for code bank 2 and the common area.

You can create Intel HEX files for each of these OMF-51 files by using the OH51 object to hex converter. The Intel HEX files you create with OH51 contain complete information for each code bank including the common area. Intel HEX files can be generated using the following OH51 object to hex converter command line.

OH51 P_ROOT.B00 HEXFILE (P_ROOT.H00)

OH51 P_ROOT.B01 HEXFILE (P_ROOT.H01)

OH51 P_ROOT.B02 HEXFILE (P_ROOT.H02)

Соседние файлы в папке HLP