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IAR Embedded Workbench for RH850 3.20.x

Creating assembler source with CFI support

In this section:

The recommended way to create an assembler language routine that handles call frame information correctly is to start with an assembler language source file created by the compiler.

  1. Start with suitable C source code, for example:

    int F(int);
int cfiExample(int i)
{
  return i + F(i);
}

  2. Compile the C source code, and make sure to create a list file that contains call frame information—the CFI directives.

    Danger

    On the command line, use the option -lA.

    Caution

    In the IDE, choose Project>Options>C/C++ Compiler>List and make sure the suboption Include call frame information is selected.

    For the source code in this example, the list file looks like this:

            NAME test

        RTMODEL "__SystemLibrary", "DLib"
        RTMODEL "__core", "g3"
        RTMODEL "__data_model", "small"
        RTMODEL "__double_size", "64"
        RTMODEL "__eight_byte_alignment", "disabled"
        RTMODEL "__enum_size", "*"
        RTMODEL "__fpu", "double"
        RTMODEL "__reg_ep", "frame"
        RTMODEL "__reg_gp_lock", "0"
        RTMODEL "__reg_r5", "brel_const"
        RTMODEL "__rt_version", "2"
            #define SHT_PROGBITS 0x1

        EXTERN _F

            PUBLIC _cfiExample
        
          CFI Names cfiNames0
          CFI StackFrame CFA SP DATA
          CFI Resource R0:32, R1:32, R2:32, SP:32, R4:32, R5:32,
                       R6:32, R7:32
          CFI Resource R8:32, R9:32, R10:32, R11:32, R12:32,
                       R13:32, R14:32
          CFI Resource R15:32, R16:32, R17:32, R18:32, R19:32,
                       R20:32, R21:32
          CFI Resource R22:32, R23:32, R24:32, R25:32, R26:32,
                       R27:32, R28:32
          CFI Resource R29:32, EP:32, LP:32, EIPC:32, EIPSW:32,
                       FEPC:32, FEPSW:32
          CFI Resource PSW:32, CTPC:32, CTPSW:32
          CFI VirtualResource ?RET:32
          CFI EndNames cfiNames0
        
              CFI Common cfiCommon0 Using cfiNames0
          CFI CodeAlign 2
          CFI DataAlign 4
          CFI ReturnAddress ?RET DATA
          CFI CFA SP+0
          CFI R0 SameValue
          CFI R1 Undefined
          CFI R2 SameValue
          CFI R4 SameValue
          CFI R5 SameValue
          CFI R6 Undefined
          CFI R7 Undefined
          CFI R8 Undefined
          CFI R9 Undefined
          CFI R10 Undefined
          CFI R11 Undefined
          CFI R12 Undefined
          CFI R13 Undefined
          CFI R14 Undefined
          CFI R15 Undefined
          CFI R16 Undefined
          CFI R17 Undefined
          CFI R18 Undefined
          CFI R19 Undefined
          CFI R20 SameValue
          CFI R21 SameValue
          CFI R22 SameValue
          CFI R23 SameValue
          CFI R24 SameValue
          CFI R25 SameValue
          CFI R26 SameValue
          CFI R27 SameValue
          CFI R28 SameValue
          CFI R29 SameValue
          CFI EP SameValue
          CFI LP Undefined
          CFI EIPC SameValue
          CFI EIPSW SameValue
          CFI FEPC SameValue
          CFI FEPSW SameValue
          CFI PSW SameValue
          CFI CTPC SameValue
          CFI CTPSW SameValue
          CFI ?RET LP
          CFI EndCommon cfiCommon0
            SECTION `.text`:CODE:NOROOT(2)
          CFI Block cfiBlock0 Using cfiCommon0
          CFI Function _cfiExample
        CODE
_cfiExample:
        PREPARE     {r29,lp},0
          CFI R29 Frame(CFA, -4)
          CFI ?RET Frame(CFA, -8)
          CFI CFA SP+8
        MOV         r6,r29
        MOV         r29,r6
          CFI FunCall _F
        JARL        _F,lp
        ADD         r29,r10
        DISPOSE     0,{r29,lp},[lp]
          CFI EndBlock cfiBlock0

            SECTION `.iar_vfe_header`:DATA:NOALLOC:NOROOT(2)
        SECTION_TYPE SHT_PROGBITS, 0
        DATA
        DC32 0
        END

    Note

    The header file cfi.h contains the macros CFNAMES and CFCOMMON0, which declare a typical names block and a typical common block. These two macros declare several resources, both concrete and virtual.