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Function RTMPStartCPU

RTMPStartCPU starts an additional CPU:

UINT RTMPStartCPU(UINT            CPU, 
                  DWORD           Flags, 
                  WORD            FS, 
                  void          * ESP, 
                  void (__cdecl * Entrypoint)(void * P), 
                  void          * Parameter);

Parameters

CPU

Index of the CPU to start. This parameter must be in the range 0 .. RTMPCPUs(...)-1 and it must not be equal to RTMPSelf().

Flags

Zero or a combination of the following flag values:

FS

Segment selector to be loaded in the target CPU's FS register. If value 0xFFFF is specified, the target CPU will use the FS value of the calling CPU.

ESP

Initial ESP value for the started CPU. This must be a DWORD aligned address pointing to the first byte beyond the stack allocated for the new CPU.

Entrypoint

C/C++ function the CPU shall execute. This function must never return!

Parameter

The parameter to be passed to function Entrypoint on the started CPU.

return value

Zero on failure and non-zero otherwise.

This function requires APIC mode and will call RTMPSetAPICMode(0) if not in APIC mode.

Like all x86 CPUs, additional application CPUs start execution in real mode. Thus, the initial startup code must reside in the first megabyte of the physical address space. RTMPStartCPU attempts to allocate space for the startup code by looking for a Nothing section with name "APBootCode". If that fails, it will try function RTAllocPhysPageAligned. If both allocations fail or the returned address is not within the first megabyte, the function fails and displays error message:

Failed to allocate AP Boot Code

To guard against such failures, it is recommended to include the following directive in the application's locator configuration file:

Locate  Nothing  APBootCode  DOSMem  4k  4k  ReadWrite

where DOSMem may be replaced with any RAM region below 1M. Section APBootCode must have a size of 4k and must be 4k aligned.

Function RTMPSelf

Function RTMPStopAll