N64 bootup and cache interfaces. More...

Files
file	n64sys.c
	N64 System Interface.
file	n64sys.h
	N64 System Interface.
Defines
#define	cache_op(op)
	Helper macro to perform cache refresh operations.
#define	UncachedAddr(_addr) ((void *)(((unsigned long)(_addr))\|0x20000000))
	Return the uncached memory address for a given address.
#define	UncachedShortAddr(_addr) ((short *)(((unsigned long)(_addr))\|0x20000000))
	Return the uncached memory address for a given address.
#define	UncachedUShortAddr(_addr) ((unsigned short *)(((unsigned long)(_addr))\|0x20000000))
	Return the uncached memory address for a given address.
#define	UncachedLongAddr(_addr) ((long *)(((unsigned long)(_addr))\|0x20000000))
	Return the uncached memory address for a given address.
#define	UncachedULongAddr(_addr) ((unsigned long *)(((unsigned long)(_addr))\|0x20000000))
	Return the uncached memory address for a given address.
#define	CachedAddr(_addr) (((void *)(((unsigned long)(_addr))&~0x20000000))
	Return the cached memory address for a given address.
#define	COUNTS_PER_SECOND (93750000/2)
	Number of updates to the count register per second.
Functions
int	sys_get_boot_cic ()
	Return the boot CIC.
void	sys_set_boot_cic (int bc)
	Set the boot CIC.
volatile unsigned long	get_ticks (void)
	Read the number of ticks since system startup.
volatile unsigned long	get_ticks_ms (void)
	Read the number of millisecounds since system startup.
void	wait_ticks (unsigned long wait)
	Spin wait until the number of ticks have elapsed.
void	wait_ms (unsigned long wait)
	Spin wait until the number of millisecounds have elapsed.
void	data_cache_hit_writeback (volatile void *addr, unsigned long length)
	Force a data cache writeback over a memory region.
void	data_cache_hit_invalidate (volatile void *addr, unsigned long length)
	Force a data cache invalidate over a memory region.
void	data_cache_hit_writeback_invalidate (volatile void *addr, unsigned long length)
	Force a data cache writeback invalidate over a memory region.
void	data_cache_index_writeback_invalidate (volatile void *addr, unsigned long length)
	Force a data cache index writeback invalidate over a memory region.
void	inst_cache_hit_writeback (volatile void *addr, unsigned long length)
	Force an instruction cache writeback over a memory region.
void	inst_cache_hit_invalidate (volatile void *addr, unsigned long length)
	Force an instruction cache invalidate over a memory region.
void	inst_cache_index_invalidate (volatile void *addr, unsigned long length)
	Force an instruction cache index invalidate over a memory region.
Variables
int	__bootcic = 6102
	Boot CIC.

Detailed Description

N64 bootup and cache interfaces.

The N64 system interface provides a way for code to interact with the memory setup on the system. This includes cache operations to invalidate or flush regions and the ability to set the boot CIC. The newlib Interface Hooks use the knowledge of the boot CIC to properly determine if the expansion pak is present, giving 4MB of additional memory. Aside from this, the MIPS r4300 uses a manual cache management strategy, where SW that requires passing buffers to and from hardware components using DMA controllers needs to ensure that cache and RDRAM are in sync. A set of operations to invalidate and/or write back cache is provided for both instruction cache and data cache.

Define Documentation

#define cache_op ( op )

Value:

addr=(void*)(((unsigned long)addr)&(~3));\
    for (;length>0;length-=4,addr+=4) \
    asm ("\tcache %0,(%1)\n"::"i" (op), "r" (addr))

Helper macro to perform cache refresh operations.

Parameters:

[in] op Operation to perform

#define CachedAddr ( _addr ) (((void *)(((unsigned long)(_addr))&~0x20000000))

Return the cached memory address for a given address.

Parameters:

[in] _addr Address in RAM to convert to a cached address

Returns:: A void pointer to the cached memory address in RAM

#define COUNTS_PER_SECOND (93750000/2)

Number of updates to the count register per second.

The count register updates at "half maximum instruction issue rate". This appears to be half the CPU clock. Every second, this many counts will have passed in the count register

#define UncachedAddr ( _addr ) ((void *)(((unsigned long)(_addr))|0x20000000))

Return the uncached memory address for a given address.

Parameters: