/* switch.h * Definitions needed for implementing context switching. * * Context switching is inherently machine dependent, since * the registers to be saved, how to set up an initial * call frame, etc, are all specific to a processor architecture. * * This file currently supports the DEC MIPS and SUN SPARC architectures. */ /* Copyright (c) 1992-1993 The Regents of the University of California. All rights reserved. See copyright.h for copyright notice and limitation of liability and disclaimer of warranty provisions. */ #ifndef SWITCH_H #define SWITCH_H #include "copyright.h" #ifdef HOST_MIPS /* Registers that must be saved during a context switch. * These are the offsets from the beginning of the Thread object, * in bytes, used in switch.s */ #define SP 0 #define S0 4 #define S1 8 #define S2 12 #define S3 16 #define S4 20 #define S5 24 #define S6 28 #define S7 32 #define FP 36 #define PC 40 /* To fork a thread, we set up its saved register state, so that * when we switch to the thread, it will start running in ThreadRoot. * * The following are the initial registers we need to set up to * pass values into ThreadRoot (for instance, containing the procedure * for the thread to run). The first set is the registers as used * by ThreadRoot; the second set is the locations for these initial * values in the Thread object -- used in Thread::AllocateStack(). */ #define InitialPC s0 #define InitialArg s1 #define WhenDonePC s2 #define StartupPC s3 #define PCState (PC/4-1) #define FPState (FP/4-1) #define InitialPCState (S0/4-1) #define InitialArgState (S1/4-1) #define WhenDonePCState (S2/4-1) #define StartupPCState (S3/4-1) #endif // HOST_MIPS #ifdef HOST_SPARC /* Registers that must be saved during a context switch. See comment above. */ #define I0 4 #define I1 8 #define I2 12 #define I3 16 #define I4 20 #define I5 24 #define I6 28 #define I7 32 /* Aliases used for clearing code. */ #define FP I6 #define PC I7 /* Registers for ThreadRoot. See comment above. */ #define InitialPC %o0 #define InitialArg %o1 #define WhenDonePC %o2 #define StartupPC %o3 #define PCState (PC/4-1) #define InitialPCState (I0/4-1) #define InitialArgState (I1/4-1) #define WhenDonePCState (I2/4-1) #define StartupPCState (I3/4-1) #endif // HOST_SPARC #ifdef HOST_SNAKE /* Registers that must be saved during a context switch. See comment above. */ #define SP 0 #define S0 4 #define S1 8 #define S2 12 #define S3 16 #define S4 20 #define S5 24 #define S6 28 #define S7 32 #define S8 36 #define S9 40 #define S10 44 #define S11 48 #define S12 52 #define S13 56 #define S14 60 #define S15 64 #define PC 68 /* Registers for ThreadRoot. See comment above. */ #define InitialPC %r3 /* S0 */ #define InitialArg %r4 #define WhenDonePC %r5 #define StartupPC %r6 #define PCState (PC/4-1) #define InitialPCState (S0/4-1) #define InitialArgState (S1/4-1) #define WhenDonePCState (S2/4-1) #define StartupPCState (S3/4-1) #endif // HOST_SNAKE #ifdef HOST_i386 /* the offsets of the registers from the beginning of the thread object */ #define _ESP 0 #define _EAX 4 #define _EBX 8 #define _ECX 12 #define _EDX 16 #define _EBP 20 #define _ESI 24 #define _EDI 28 #define _PC 32 /* These definitions are used in Thread::AllocateStack(). */ #define PCState (_PC/4-1) #define FPState (_EBP/4-1) #define InitialPCState (_ESI/4-1) #define InitialArgState (_EDX/4-1) #define WhenDonePCState (_EDI/4-1) #define StartupPCState (_ECX/4-1) #define InitialPC %esi #define InitialArg %edx #define WhenDonePC %edi #define StartupPC %ecx #endif #endif // SWITCH_H
