Issue with powerpc-eabivle-gcc.exe, revision 4.9.4: The builtin __builtin_ppc_get_timebase() fails to compile in VLE mode

[peter_vranken]

The builtin __builtin_ppc_get_timebase() fails to compile in VLE mode of the compiler powerpc-eabivle-gcc.exe, revision 4.9.4. The error message is:

bin/ppc/DEBUG/obj/mai_main.s:73: Error: operand out of range (7 is not between 0 and 3)

The C code is

    uint64_t tiStart = __builtin_ppc_get_timebase();

The assembly listing looks like:

 .loc 1 414 0
 mftbu %r4  # D.18848
 mftb %r5  # D.18848
 mftbu %r7  #
 cmpw %cr7,%r4,%r7  #, D.18848,
 e_bne %cr7,$-16  #

Using CR7 seems to be not available with VLE instructions yet it is used in the instructions emitted by the compiler.

[peter_vranken]

Here is my own work around. Place the code into a header file xxx....h and use XXX_PPC_GET_TIMEBASE()  instead of __builtin_ppc_get_timebase():

#include <stdint.h>

#include <stdbool.h>

#ifdef __VLE__
# define XXX_PPC_GET_TIMEBASE() xxx_ppc_get_timebase()
#else
# define XXX_PPC_GET_TIMEBASE() __builtin_ppc_get_timebase()
#endif

#ifdef __VLE__
/**
 * Return the world time elapsed since power up in units of CPU clock ticks. This function
 * is a substitute for the GCC builtin \a __builtin_ppc_get_timebase(), which fails to compile
 * with MinGW-powerpc-eabivle-4.9.4.
 *   @return Get the world time elapsed since power up in units of 8.333... ns; our startup
 * code configures the CPU clock frequency to 120 Mhz=1/(8+1/3)ns.
 *   @remark
 * The function is compiled only in VLE mode, use \a __builtin_ppc_get_timebase() instead
 * in Book E applications.
 */
static inline uint64_t xxx_ppc_get_timebase()
{
    uint32_t TBU, TBU2nd, TBL;
    while(true)
    {
        asm volatile ( /* AssemblerTemplate */
                       "mfspr %0, 269\n\r" // SPR 269 = TBU
                       "mfspr %2, 268\n\r" // SPR 268 = TBL
                       "mfspr %1, 269\n\r" // SPR 269 = TBU
                     : /* OutputOperands */ "=r" (TBU),  "=r" (TBU2nd), "=r" (TBL)
                     : /* InputOperands */
                     : /* Clobbers */
                     );
        if(TBU == TBU2nd)
            break;
    }
    return ((uint64_t)TBU << 32) | TBL;
   
} /* End of xxx_ppc_get_timebase */
#endif

[alexanderfedoto]

peter_vranken‌

Thank you for reporting. I created a ticket for that #CMPE200GCC-183

[peter_vranken]

The MCU is a MPC5643L in LSM. The compiler is commanded to generate code for e200z4.

The command line is:

C:/ProgramFiles/MinGW-powerpc-eabivle-4.9.4/bin/powerpc-eabivle-gcc.exe -c -mcpu=e200z4 -mbig-endian -mvle -mspe -misel=yes -meabi -msdata=default -G8 -mregnames -mhard-float -fshort-double -mno-string -fno-common -fno-exceptions -ffunction-sections -fdata-sections -fshort-enums -fdiagnostics-show-option -finline-functions -fzero-initialized-in-bss -fno-tree-loop-optimize -Wall -Wno-main -Wno-old-style-declaration -Winline -Wextra -Wstrict-overflow=4 -Wmissing-declarations -Wno-parentheses -Wdiv-by-zero -Wcast-align -Wformat -Wformat-security -Wignored-qualifiers -Wsign-conversion -Wsign-compare -Werror=missing-declarations -Werror=implicit-function-declaration -Wno-nested-externs -Werror=int-to-pointer-cast -Werror=pointer-sign -Werror=pointer-to-int-cast -Werror=return-local-addr -MMD -Wa,-a=bin/ppc/DEBUG/obj/gsl_systemLoad.lst -std=gnu11 -Icode/ -Icode/RTOS/ -Icode/serial/ -Icode/startup/ -DDEBUG  -save-temps=obj -fverbose-asm  -g3 -gdwarf-2 -Og -o bin/ppc/DEBUG/obj/gsl_systemLoad.o code/RTOS/gsl_systemLoad.c

Compiler output:
bin/ppc/DEBUG/obj/gsl_systemLoad.s: Assembler messages:
bin/ppc/DEBUG/obj/gsl_systemLoad.s:88: Error: operand out of range (7 is not between 0 and 3)
bin/ppc/DEBUG/obj/gsl_systemLoad.s:113: Error: operand out of range (7 is not between 0 and 3)

Assembler listing:

.LVL0:
 .loc 1 128 0
 mftbu %r26  # tiStart
 mftb %r27  # tiStart
 mftbu %r5  #
 cmpw %cr7,%r26,%r5  #, tiStart,
 e_bne %cr7,$-16  #

[martin_kovar]

Hello,

could you please clarify, which microcontroller you use?

Regards,

Martin