hal_misc.c File Reference

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Detailed Description

HAL miscellaneous functions.

Author:

nickg, jlarmour

Date:

1999-02-18

This file contains miscellaneous functions provided by the HAL.

Definition in file hal_misc.c.

Go to the source code of this file.

Functions
void	cyg_hal_invoke_constructors (void)
	This calls static constructors before program start.
cyg_uint32	hal_lsbit_index (cyg_uint32 mask)
	Determine the index of the ls bit of the supplied mask.
cyg_uint32	hal_msbit_index (cyg_uint32 mask)
	Determine the index of the ms bit of the supplied mask.
externC cyg_uint32	hal_arch_default_isr (CYG_ADDRWORD vector, CYG_ADDRWORD data)
	Default architecture interrupt service routine.
externC void	__handle_exception (void)
	GDB exception handler.
void	cyg_hal_exception_handler (HAL_SavedRegisters *regs, CYG_WORD vector)
	First level C exception handler.
externC void	hal_idle_thread_action (cyg_uint32 loop_count)
	Idle thread action called from idle thread.
void	h8s_reset_manual (void)
	Resets board by jumping to manual reset vector.
Variables
cyg_bool	cyg_hal_stop_constructors
	Set to 1 when constructors should no longer be invoked.
externC HAL_SavedRegisters *	_hal_registers
	saved machine state for GDB

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Function Documentation

externC void __handle_exception (  void   )

GDB exception handler. Referenced by cyg_hal_exception_handler().

void cyg_hal_exception_handler (  HAL_SavedRegisters *  regs, CYG_WORD  vector )

First level C exception handler. This function is called from the exception VSR. It usually does extra decoding of the exception and invokes any special handlers for things like FPU traps, bus errors or memory exceptions. If there is nothing special to be done for an exception, then it either calls into the GDB stubs, by calling __handle_exception(), or invokes the kernel by calling cyg_hal_deliver_exception() Parameters: regs  Points to saved machine stack on stack vector  Exception vector Definition at line 231 of file hal_misc.c. References __handle_exception(), _hal_registers, and cyg_hal_deliver_exception(). { // // if GDB is included then we let GDB handle the exception // #ifdef CYGDBG_HAL_DEBUG_GDB_INCLUDE_STUBS // // Set the pointer to the registers of the current exception // context. At entry the GDB stub will expand the // HAL_SavedRegisters structure into a (bigger) register array. // _hal_registers = regs; __handle_exception(); #endif // // If exception handling is enabled for hall then // #if defined(CYGPKG_HAL_EXCEPTIONS) // // We should decode the vector and pass a more appropriate // value as the second argument. For now we simply pass a // pointer to the saved registers. We should also divert // breakpoint and other debug vectors into the debug stubs. // cyg_hal_deliver_exception( vector, (CYG_ADDRWORD)regs ); #endif return; }

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void cyg_hal_invoke_constructors (  void   )

This calls static constructors before program start. This calls the constructors for all static objects before the program starts. eCos relies on these being called in the correct order for it to function correctly. The exact way in which constructors are handled may differ between architectures, although most use a simple table of function pointers between labels __CTOR_LIST__ and __CTOR_END__ which must called in order from the top down. Generally, this function can be copied directly from an existing architecture HAL. Definition at line 106 of file hal_misc.c. References cyg_hal_stop_constructors. { typedef void (*pfunc) (void); extern pfunc _CTOR_LIST__[]; extern pfunc _CTOR_END__[]; #ifdef CYGSEM_HAL_STOP_CONSTRUCTORS_ON_FLAG static pfunc *p = &_CTOR_END__[-1]; cyg_hal_stop_constructors = 0; for (; p >= _CTOR_LIST__; p--) { (*p) (); if (cyg_hal_stop_constructors) { p--; break; } } #else pfunc *p; for (p = &_CTOR_END__[-1]; p >= _CTOR_LIST__; p--) (*p) (); #endif } // cyg_hal_invoke_constructors()

void h8s_reset_manual (  void   )

Resets board by jumping to manual reset vector. This istruction will bring us to the to the address stored in the exception vector MANUAL RESET of the hardware vector table. This will bring us to _start. Note: Normally this should be the same for the whole H8S architecture. But you can overwrite it in variant or platform part by defining CYGPKG_HAL_H8S_MRESET_DEFINED Definition at line 297 of file hal_misc.c. { __asm__ ("jmp @@4\n\t"); }

externC cyg_uint32 hal_arch_default_isr (  CYG_ADDRWORD  vector, CYG_ADDRWORD  data )

Default architecture interrupt service routine. The real default ISR, hal_default_isr, is in hal/common/.../src/hal_misc.c and calls this architecture ISR. Normally this function should just return Parameters: vector  Interrupt vector data  Points to some interrupt data Returns: Zero Definition at line 208 of file hal_misc.c. { return 0; }

externC void hal_idle_thread_action (  cyg_uint32  loop_count  )

Idle thread action called from idle thread. This function is called from the idle thread via the HAL_IDLE_THREAD_ACTION() macro, if so defined. While normally this function does nothing, during development this is often a good place to report various important system parameters on LCDs, LED or other displays. This function can also monitor system state and report any anomalies. If the architecture supports a halt instruction then this is a good place to put an inline assembly fragment to execute it. It is also a good place to handle any power saving activity. Parameters: loop_count  Counter provided by idle thread - counts how often idle thread was executed. Definition at line 278 of file hal_misc.c. { }

cyg_uint32 hal_lsbit_index (  cyg_uint32  mask  )

Determine the index of the ls bit of the supplied mask. Because the H8S does not support these by hardware we have to implement the macro HAL_LSBIT_INDEX( index, mask ) as call to this function Parameters: mask  Bit mask to be processed Returns: Index of ls bit in mask Definition at line 143 of file hal_misc.c. { cyg_uint32 n = mask; static const signed char tab[64] = { -1, 0, 1, 12, 2, 6, 0, 13, 3, 0, 7, 0, 0, 0, 0, 14, 10, 4, 0, 0, 8, 0, 0, 25, 0, 0, 0, 0, 0, 21, 27 , 15, 31, 11, 5, 0, 0, 0, 0, 0, 9, 0, 0, 24, 0, 0 , 20, 26, 30, 0, 0, 0, 0, 23, 0, 19, 29, 0, 22, 18, 28, 17, 16, 0 }; n &= ~(n-1UL); n = (n<<16)-n; n = (n<<6)+n; n = (n<<4)+n; return tab[n>>26]; }

cyg_uint32 hal_msbit_index (  cyg_uint32  mask  )

Determine the index of the ms bit of the supplied mask. Because the H8S does not support these by hardware we have to implement the macro HAL_MSBIT_INDEX( index, mask ) as call to this function Parameters: mask  Bit mask to be processed. Returns: Index of ms bit in supplied mask Definition at line 174 of file hal_misc.c. { cyg_uint32 x = mask; cyg_uint32 w; // Phase 1: make word with all ones from that one to the right x |= x >> 16; x |= x >> 8; x |= x >> 4; x |= x >> 2; x |= x >> 1; // Phase 2: calculate number of "1" bits in the word w = (x & 0x55555555) + ((x >> 1) & 0x55555555); w = (w & 0x33333333) + ((w >> 2) & 0x33333333); w = w + (w >> 4); w = (w & 0x000F000F) + ((w >> 8) & 0x000F000F); return (cyg_uint32)((w + (w >> 16)) & 0xFF) - 1; }

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Variable Documentation

externC HAL_SavedRegisters* _hal_registers

saved machine state for GDB Definition at line 216 of file hal_misc.c. Referenced by cyg_hal_exception_handler().

cyg_bool cyg_hal_stop_constructors

Set to 1 when constructors should no longer be invoked. It is up to some other package to deal with the rest of the constructors. In the current version this is only possible with the C library. Definition at line 89 of file hal_misc.c. Referenced by cyg_hal_invoke_constructors().

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