You will probably like to look at a startup code from one code example for the board EK-LM3S8962 given with stellarisware... it also contains inline assemby instructions
file:
startup_css.c
//*****************************************************************************
//
// startup_ccs.c - Startup code for use with TI's Code Composer Studio.
//
// Copyright (c) 2009-2011 Texas Instruments Incorporated. All rights reserved.
// Software License Agreement
//
// Texas Instruments (TI) is supplying this software for use solely and
// exclusively on TI's microcontroller products. The software is owned by
// TI and/or its suppliers, and is protected under applicable copyright
// laws. You may not combine this software with "viral" open-source
// software in order to form a larger program.
//
// THIS SOFTWARE IS PROVIDED "AS IS" AND WITH ALL FAULTS.
// NO WARRANTIES, WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT
// NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. TI SHALL NOT, UNDER ANY
// CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
// DAMAGES, FOR ANY REASON WHATSOEVER.
//
// This is part of revision 6852 of the EK-LM3S8962 Firmware Package.
//
//*****************************************************************************
//*****************************************************************************
//
// Forward declaration of the default fault handlers.
//
//*****************************************************************************
void ResetISR(void);
static void NmiSR(void);
static void FaultISR(void);
static void IntDefaultHandler(void);
//*****************************************************************************
//
// External declaration for the reset handler that is to be called when the
// processor is started
//
//*****************************************************************************
extern void _c_int00(void);
//*****************************************************************************
//
// Linker variable that marks the top of the stack.
//
//*****************************************************************************
extern unsigned long __STACK_TOP;
//*****************************************************************************
//
// External declarations for the interrupt handlers used by the application.
//
//*****************************************************************************
extern void lwIPEthernetIntHandler(void);
extern void SysTickHandler(void);
//*****************************************************************************
//
// The vector table. Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000 or at the start of
// the program if located at a start address other than 0.
//
//*****************************************************************************
#pragma DATA_SECTION(g_pfnVectors, ".intvecs")
void (* const g_pfnVectors[])(void) =
{
(void (*)(void))((unsigned long)&__STACK_TOP),
// The initial stack pointer
ResetISR, // The reset handler
NmiSR, // The NMI handler
FaultISR, // The hard fault handler
IntDefaultHandler, // The MPU fault handler
IntDefaultHandler, // The bus fault handler
IntDefaultHandler, // The usage fault handler
0, // Reserved
0, // Reserved
0, // Reserved
0, // Reserved
IntDefaultHandler, // SVCall handler
IntDefaultHandler, // Debug monitor handler
0, // Reserved
IntDefaultHandler, // The PendSV handler
SysTickHandler, // The SysTick handler
IntDefaultHandler, // GPIO Port A
IntDefaultHandler, // GPIO Port B
IntDefaultHandler, // GPIO Port C
IntDefaultHandler, // GPIO Port D
IntDefaultHandler, // GPIO Port E
IntDefaultHandler, // UART0 Rx and Tx
IntDefaultHandler, // UART1 Rx and Tx
IntDefaultHandler, // SSI0 Rx and Tx
IntDefaultHandler, // I2C0 Master and Slave
IntDefaultHandler, // PWM Fault
IntDefaultHandler, // PWM Generator 0
IntDefaultHandler, // PWM Generator 1
IntDefaultHandler, // PWM Generator 2
IntDefaultHandler, // Quadrature Encoder 0
IntDefaultHandler, // ADC Sequence 0
IntDefaultHandler, // ADC Sequence 1
IntDefaultHandler, // ADC Sequence 2
IntDefaultHandler, // ADC Sequence 3
IntDefaultHandler, // Watchdog timer
IntDefaultHandler, // Timer 0 subtimer A
IntDefaultHandler, // Timer 0 subtimer B
IntDefaultHandler, // Timer 1 subtimer A
IntDefaultHandler, // Timer 1 subtimer B
IntDefaultHandler, // Timer 2 subtimer A
IntDefaultHandler, // Timer 2 subtimer B
IntDefaultHandler, // Analog Comparator 0
IntDefaultHandler, // Analog Comparator 1
IntDefaultHandler, // Analog Comparator 2
IntDefaultHandler, // System Control (PLL, OSC, BO)
IntDefaultHandler, // FLASH Control
IntDefaultHandler, // GPIO Port F
IntDefaultHandler, // GPIO Port G
IntDefaultHandler, // GPIO Port H
IntDefaultHandler, // UART2 Rx and Tx
IntDefaultHandler, // SSI1 Rx and Tx
IntDefaultHandler, // Timer 3 subtimer A
IntDefaultHandler, // Timer 3 subtimer B
IntDefaultHandler, // I2C1 Master and Slave
IntDefaultHandler, // Quadrature Encoder 1
IntDefaultHandler, // CAN0
IntDefaultHandler, // CAN1
IntDefaultHandler, // CAN2
lwIPEthernetIntHandler, // Ethernet
IntDefaultHandler // Hibernate
};
//*****************************************************************************
//
// This is the code that gets called when the processor first starts execution
// following a reset event. Only the absolutely necessary set is performed,
// after which the application supplied entry() routine is called. Any fancy
// actions (such as making decisions based on the reset cause register, and
// resetting the bits in that register) are left solely in the hands of the
// application.
//
//*****************************************************************************
void
ResetISR(void)
{
//
// Jump to the CCS C Initialization Routine.
//
__asm(" .global _c_int00\n"
" b.w _c_int00");
}
//*****************************************************************************
//
// This is the code that gets called when the processor receives a NMI. This
// simply enters an infinite loop, preserving the system state for examination
// by a debugger.
//
//*****************************************************************************
static void
NmiSR(void)
{
//
// Enter an infinite loop.
//
while(1)
{
}
}
//*****************************************************************************
//
// This is the code that gets called when the processor receives a fault
// interrupt. This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
FaultISR(void)
{
//
// Enter an infinite loop.
//
while(1)
{
}
}
//*****************************************************************************
//
// This is the code that gets called when the processor receives an unexpected
// interrupt. This simply enters an infinite loop, preserving the system state
// for examination by a debugger.
//
//*****************************************************************************
static void
IntDefaultHandler(void)
{
//
// Go into an infinite loop.
//
while(1)
{
}
}
I've read somewhere that
extern void _c_int00(void); is intrinsics for void main(void);
And I think you can probably edit ResetISR(void) to make a call to your external start routine, or even replace the Reset Handler in the interrupt vector for your start routine.
some code using Predefined Macro Names for Cross compiler definitions of interrupt service routine
part of the code from a code composer example.
I also found that Code Composer always predefines the macro __TI_COMPILER_VERSION__
#ifdef __GNUC__
#define portSET_INTERRUPT_MASK() \
__asm volatile \
( \
" mov r0, %0 \n" \
" msr basepri, r0 \n" \
::"i"(portSYSCALL_INTERRUPT_PRIORITY):"r0" \
)
#elif defined(__ARMCC_VERSION)
extern void portSET_INTERRUPT_MASK(void);
#elif defined(__IAR_SYSTEMS_ICC__)
#define portSET_INTERRUPT_MASK() \
__asm \
( \
" mov r0, #191 \n" \
" msr basepri, r0 \n" \
)
#else
#error Unknown compiler!
#endif
I hope it helps ..
regards,
Ricardo