old-cross-binutils/sim/arm/armsupp.c

/*  armsupp.c -- ARMulator support code:  ARM6 Instruction Emulator.
    Copyright (C) 1994 Advanced RISC Machines Ltd.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */

#include "armdefs.h"
#include "armemu.h"

/***************************************************************************\
*                    Definitions for the support routines                   *
\***************************************************************************/

ARMword ARMul_GetReg(ARMul_State *state, unsigned mode, unsigned reg) ;
void ARMul_SetReg(ARMul_State *state, unsigned mode, unsigned reg, ARMword value) ;
ARMword ARMul_GetPC(ARMul_State *state) ;
ARMword ARMul_GetNextPC(ARMul_State *state) ;
void ARMul_SetPC(ARMul_State *state, ARMword value) ;
ARMword ARMul_GetR15(ARMul_State *state) ;
void ARMul_SetR15(ARMul_State *state, ARMword value) ;

ARMword ARMul_GetCPSR(ARMul_State *state) ;
void ARMul_SetCPSR(ARMul_State *state, ARMword value) ;
void ARMul_FixCPSR(ARMul_State *state, ARMword instr, ARMword rhs) ;
ARMword ARMul_GetSPSR(ARMul_State *state, ARMword mode) ;
void ARMul_SetSPSR(ARMul_State *state, ARMword mode, ARMword value) ;
void ARMul_FixSPSR(ARMul_State *state, ARMword instr, ARMword rhs) ;

void ARMul_CPSRAltered(ARMul_State *state) ;
void ARMul_R15Altered(ARMul_State *state) ;

ARMword ARMul_SwitchMode(ARMul_State *state,ARMword oldmode, ARMword newmode) ;
static ARMword ModeToBank(ARMul_State *state,ARMword mode) ;

unsigned ARMul_NthReg(ARMword instr, unsigned number) ;

void ARMul_NegZero(ARMul_State *state, ARMword result) ;
void ARMul_AddCarry(ARMul_State *state, ARMword a, ARMword b, ARMword result) ;
void ARMul_AddOverflow(ARMul_State *state, ARMword a, ARMword b, ARMword result) ;
void ARMul_SubCarry(ARMul_State *state, ARMword a, ARMword b, ARMword result) ;
void ARMul_SubOverflow(ARMul_State *state, ARMword a, ARMword b, ARMword result) ;

void ARMul_LDC(ARMul_State *state,ARMword instr,ARMword address) ;
void ARMul_STC(ARMul_State *state,ARMword instr,ARMword address) ;
void ARMul_MCR(ARMul_State *state,ARMword instr, ARMword source) ;
ARMword ARMul_MRC(ARMul_State *state,ARMword instr) ;
void ARMul_CDP(ARMul_State *state,ARMword instr) ;
void ARMul_UndefInstr(ARMul_State *state,ARMword instr) ;
unsigned IntPending(ARMul_State *state) ;

ARMword ARMul_Align(ARMul_State *state, ARMword address, ARMword data) ;

void ARMul_ScheduleEvent(ARMul_State *state, unsigned long delay,
                         unsigned (*what)()) ;
void ARMul_EnvokeEvent(ARMul_State *state) ;
unsigned long ARMul_Time(ARMul_State *state) ;
static void EnvokeList(ARMul_State *state, unsigned long from, unsigned long to) ;

struct EventNode { /* An event list node */
      unsigned (*func)() ; /* The function to call */
      struct EventNode *next ;
      } ;

/***************************************************************************\
* This routine returns the value of a register from a mode.                 *
\***************************************************************************/

ARMword ARMul_GetReg(ARMul_State *state, unsigned mode, unsigned reg)
{mode &= MODEBITS ;
 if (mode != state->Mode)
    return(state->RegBank[ModeToBank(state,(ARMword)mode)][reg]) ;
 else
    return(state->Reg[reg]) ;
}

/***************************************************************************\
* This routine sets the value of a register for a mode.                     *
\***************************************************************************/

void ARMul_SetReg(ARMul_State *state, unsigned mode, unsigned reg, ARMword value)
{mode &= MODEBITS ;
 if (mode != state->Mode)
    state->RegBank[ModeToBank(state,(ARMword)mode)][reg] = value ;
 else
    state->Reg[reg] = value ;
}

/***************************************************************************\
* This routine returns the value of the PC, mode independently.             *
\***************************************************************************/

ARMword ARMul_GetPC(ARMul_State *state)
{if (state->Mode > SVC26MODE)
    return(state->Reg[15]) ;
 else
    return(R15PC) ;
}

/***************************************************************************\
* This routine returns the value of the PC, mode independently.             *
\***************************************************************************/

ARMword ARMul_GetNextPC(ARMul_State *state)
{if (state->Mode > SVC26MODE)
    return(state->Reg[15] + isize) ;
 else
    return((state->Reg[15] + isize) & R15PCBITS) ;
}

/***************************************************************************\
* This routine sets the value of the PC.                                    *
\***************************************************************************/

void ARMul_SetPC(ARMul_State *state, ARMword value)
{if (ARMul_MODE32BIT)
    state->Reg[15] = value & PCBITS ;
 else
    state->Reg[15] = R15CCINTMODE | (value & R15PCBITS) ;
 FLUSHPIPE ;
}

/***************************************************************************\
* This routine returns the value of register 15, mode independently.        *
\***************************************************************************/

ARMword ARMul_GetR15(ARMul_State *state)
{if (state->Mode > SVC26MODE)
    return(state->Reg[15]) ;
 else
    return(R15PC | ECC | ER15INT | EMODE) ;
}

/***************************************************************************\
* This routine sets the value of Register 15.                               *
\***************************************************************************/

void ARMul_SetR15(ARMul_State *state, ARMword value)
{
 if (ARMul_MODE32BIT)
    state->Reg[15] = value & PCBITS ;
 else {
    state->Reg[15] = value ;
    ARMul_R15Altered(state) ;
    }
 FLUSHPIPE ;
}

/***************************************************************************\
* This routine returns the value of the CPSR                                *
\***************************************************************************/

ARMword ARMul_GetCPSR(ARMul_State *state)
{
 return(CPSR) ;
 }

/***************************************************************************\
* This routine sets the value of the CPSR                                   *
\***************************************************************************/

void ARMul_SetCPSR(ARMul_State *state, ARMword value)
{state->Cpsr = CPSR ;
 SETPSR(state->Cpsr,value) ;
 ARMul_CPSRAltered(state) ;
 }

/***************************************************************************\
* This routine does all the nasty bits involved in a write to the CPSR,     *
* including updating the register bank, given a MSR instruction.                    *
\***************************************************************************/

void ARMul_FixCPSR(ARMul_State *state, ARMword instr, ARMword rhs)
{state->Cpsr = CPSR ;
 if (state->Bank==USERBANK) { /* Only write flags in user mode */
    if (BIT(19)) {
       SETCC(state->Cpsr,rhs) ;
       }
    }
 else { /* Not a user mode */
    if (BITS(16,19)==9) SETPSR(state->Cpsr,rhs) ;
    else if (BIT(16)) SETINTMODE(state->Cpsr,rhs) ;
    else if (BIT(19)) SETCC(state->Cpsr,rhs) ;
    }
 ARMul_CPSRAltered(state) ;
 }

/***************************************************************************\
* Get an SPSR from the specified mode                                       *
\***************************************************************************/

ARMword ARMul_GetSPSR(ARMul_State *state, ARMword mode)
{ARMword bank = ModeToBank(state,mode & MODEBITS) ;
 if (bank == USERBANK || bank == DUMMYBANK)
    return(CPSR) ;
 else
    return(state->Spsr[bank]) ;
}

/***************************************************************************\
* This routine does a write to an SPSR                                      *
\***************************************************************************/

void ARMul_SetSPSR(ARMul_State *state, ARMword mode, ARMword value)
{ARMword bank = ModeToBank(state,mode & MODEBITS) ;
 if (bank != USERBANK && bank !=DUMMYBANK)
    state->Spsr[bank] = value ;
}

/***************************************************************************\
* This routine does a write to the current SPSR, given an MSR instruction   *
\***************************************************************************/

void ARMul_FixSPSR(ARMul_State *state, ARMword instr, ARMword rhs)
{if (state->Bank != USERBANK && state->Bank !=DUMMYBANK) {
    if (BITS(16,19)==9) SETPSR(state->Spsr[state->Bank],rhs) ;
    else if (BIT(16)) SETINTMODE(state->Spsr[state->Bank],rhs) ;
    else if (BIT(19)) SETCC(state->Spsr[state->Bank],rhs) ;
    }
}

/***************************************************************************\
* This routine updates the state of the emulator after the Cpsr has been    *
* changed.  Both the processor flags and register bank are updated.         *
\***************************************************************************/

void ARMul_CPSRAltered(ARMul_State *state)
{ARMword oldmode ;

 if (state->prog32Sig == LOW)
    state->Cpsr &= (CCBITS | INTBITS | R15MODEBITS) ;
 oldmode = state->Mode ;
 if (state->Mode != (state->Cpsr & MODEBITS)) {
    state->Mode = ARMul_SwitchMode(state,state->Mode,state->Cpsr & MODEBITS) ;
    state->NtransSig = (state->Mode & 3)?HIGH:LOW ;
    }

 ASSIGNINT(state->Cpsr & INTBITS) ;
 ASSIGNN((state->Cpsr & NBIT) != 0) ;
 ASSIGNZ((state->Cpsr & ZBIT) != 0) ;
 ASSIGNC((state->Cpsr & CBIT) != 0) ;
 ASSIGNV((state->Cpsr & VBIT) != 0) ;
#ifdef MODET
 ASSIGNT((state->Cpsr & TBIT) != 0);
#endif

 if (oldmode > SVC26MODE) {
    if (state->Mode <= SVC26MODE) {
       state->Emulate = CHANGEMODE ;
       state->Reg[15] = ECC | ER15INT | EMODE | R15PC ;
       }
    }
 else {
    if (state->Mode > SVC26MODE) {
       state->Emulate = CHANGEMODE ;
       state->Reg[15] = R15PC ;
       }
    else
       state->Reg[15] = ECC | ER15INT | EMODE | R15PC ;
    }

}

/***************************************************************************\
* This routine updates the state of the emulator after register 15 has      *
* been changed.  Both the processor flags and register bank are updated.    *
* This routine should only be called from a 26 bit mode.                    *
\***************************************************************************/

void ARMul_R15Altered(ARMul_State *state)
{
 if (state->Mode != R15MODE) {
    state->Mode = ARMul_SwitchMode(state,state->Mode,R15MODE) ;
    state->NtransSig = (state->Mode & 3)?HIGH:LOW ;
    }
 if (state->Mode > SVC26MODE)
    state->Emulate = CHANGEMODE ;
 ASSIGNR15INT(R15INT) ;
 ASSIGNN((state->Reg[15] & NBIT) != 0) ;
 ASSIGNZ((state->Reg[15] & ZBIT) != 0) ;
 ASSIGNC((state->Reg[15] & CBIT) != 0) ;
 ASSIGNV((state->Reg[15] & VBIT) != 0) ;
}

/***************************************************************************\
* This routine controls the saving and restoring of registers across mode   *
* changes.  The regbank matrix is largely unused, only rows 13 and 14 are   *
* used across all modes, 8 to 14 are used for FIQ, all others use the USER  *
* column.  It's easier this way.  old and new parameter are modes numbers.  *
* Notice the side effect of changing the Bank variable.                     *
\***************************************************************************/

ARMword ARMul_SwitchMode(ARMul_State *state,ARMword oldmode, ARMword newmode)
{unsigned i ;

 oldmode = ModeToBank(state,oldmode) ;
 state->Bank = ModeToBank(state,newmode) ;
 if (oldmode != state->Bank) { /* really need to do it */
    switch (oldmode) { /* save away the old registers */
       case USERBANK  :
       case IRQBANK   :
       case SVCBANK   :
       case ABORTBANK :
       case UNDEFBANK : if (state->Bank == FIQBANK)
                           for (i = 8 ; i < 13 ; i++)
                              state->RegBank[USERBANK][i] = state->Reg[i] ;
                        state->RegBank[oldmode][13] = state->Reg[13] ;
                        state->RegBank[oldmode][14] = state->Reg[14] ;
                        break ;
       case FIQBANK   : for (i = 8 ; i < 15 ; i++)
                           state->RegBank[FIQBANK][i] = state->Reg[i] ;
                        break ;
       case DUMMYBANK : for (i = 8 ; i < 15 ; i++)
                           state->RegBank[DUMMYBANK][i] = 0 ;
                        break ;

       }
    switch (state->Bank) { /* restore the new registers */
       case USERBANK  :
       case IRQBANK   :
       case SVCBANK   :
       case ABORTBANK :
       case UNDEFBANK : if (oldmode == FIQBANK)
                           for (i = 8 ; i < 13 ; i++)
                              state->Reg[i] = state->RegBank[USERBANK][i] ;
                        state->Reg[13] = state->RegBank[state->Bank][13] ;
                        state->Reg[14] = state->RegBank[state->Bank][14] ;
                        break ;
       case FIQBANK  : for (i = 8 ; i < 15 ; i++)
                           state->Reg[i] = state->RegBank[FIQBANK][i] ;
                        break ;
       case DUMMYBANK : for (i = 8 ; i < 15 ; i++)
                           state->Reg[i] = 0 ;
                        break ;
       } /* switch */
    } /* if */
    return(newmode) ;
}

/***************************************************************************\
* Given a processor mode, this routine returns the register bank that       *
* will be accessed in that mode.                                            *
\***************************************************************************/

static ARMword ModeToBank(ARMul_State *state, ARMword mode)
{static ARMword bankofmode[] = {USERBANK,  FIQBANK,   IRQBANK,   SVCBANK,
                                DUMMYBANK, DUMMYBANK, DUMMYBANK, DUMMYBANK,
                                DUMMYBANK, DUMMYBANK, DUMMYBANK, DUMMYBANK,
                                DUMMYBANK, DUMMYBANK, DUMMYBANK, DUMMYBANK,
                                USERBANK,  FIQBANK,   IRQBANK,   SVCBANK,
                                DUMMYBANK, DUMMYBANK, DUMMYBANK, ABORTBANK,
                                DUMMYBANK, DUMMYBANK, DUMMYBANK, UNDEFBANK
                                } ;

 if (mode > UNDEF32MODE)
    return(DUMMYBANK) ;
 else
    return(bankofmode[mode]) ;
 }

/***************************************************************************\
* Returns the register number of the nth register in a reg list.            *
\***************************************************************************/

unsigned ARMul_NthReg(ARMword instr, unsigned number)
{unsigned bit, upto ;

 for (bit = 0, upto = 0 ; upto <= number ; bit++)
    if (BIT(bit)) upto++ ;
 return(bit - 1) ;
}

/***************************************************************************\
* Assigns the N and Z flags depending on the value of result                *
\***************************************************************************/

void ARMul_NegZero(ARMul_State *state, ARMword result)
{
 if (NEG(result)) { SETN ; CLEARZ ; }
 else if (result == 0) { CLEARN ; SETZ ; }
 else { CLEARN ; CLEARZ ; } ;
 }

/***************************************************************************\
* Assigns the C flag after an addition of a and b to give result            *
\***************************************************************************/

void ARMul_AddCarry(ARMul_State *state, ARMword a,ARMword b,ARMword result)
{
 ASSIGNC( (NEG(a) && NEG(b)) ||
          (NEG(a) && POS(result)) ||
          (NEG(b) && POS(result)) ) ;
 }

/***************************************************************************\
* Assigns the V flag after an addition of a and b to give result            *
\***************************************************************************/

void ARMul_AddOverflow(ARMul_State *state, ARMword a,ARMword b,ARMword result)
{
 ASSIGNV( (NEG(a) && NEG(b) && POS(result)) ||
          (POS(a) && POS(b) && NEG(result)) ) ;
 }

/***************************************************************************\
* Assigns the C flag after an subtraction of a and b to give result         *
\***************************************************************************/

void ARMul_SubCarry(ARMul_State *state, ARMword a,ARMword b,ARMword result)
{
ASSIGNC( (NEG(a) && POS(b)) ||
         (NEG(a) && POS(result)) ||
         (POS(b) && POS(result)) ) ;
}

/***************************************************************************\
* Assigns the V flag after an subtraction of a and b to give result         *
\***************************************************************************/

void ARMul_SubOverflow(ARMul_State *state,ARMword a,ARMword b,ARMword result)
{
ASSIGNV( (NEG(a) && POS(b) && POS(result)) ||
         (POS(a) && NEG(b) && NEG(result)) ) ;
}

/***************************************************************************\
* This function does the work of generating the addresses used in an        *
* LDC instruction.  The code here is always post-indexed, it's up to the    *
* caller to get the input address correct and to handle base register       *
* modification. It also handles the Busy-Waiting.                           *
\***************************************************************************/

void ARMul_LDC(ARMul_State *state,ARMword instr,ARMword address)
{unsigned cpab ;
 ARMword data ;

 UNDEF_LSCPCBaseWb ;
 if (ADDREXCEPT(address)) {
    INTERNALABORT(address) ;
    }
 cpab = (state->LDC[CPNum])(state,ARMul_FIRST,instr,0) ;
 while (cpab == ARMul_BUSY) {
    ARMul_Icycles(state,1,0) ;
    if (IntPending(state)) {
       cpab = (state->LDC[CPNum])(state,ARMul_INTERRUPT,instr,0) ;
       return ;
       }
    else
       cpab = (state->LDC[CPNum])(state,ARMul_BUSY,instr,0) ;
    }
 if (cpab == ARMul_CANT) {
    CPTAKEABORT ;
    return ;
    }
 cpab = (state->LDC[CPNum])(state,ARMul_TRANSFER,instr,0) ;
 data = ARMul_LoadWordN(state,address) ;
 BUSUSEDINCPCN ;
 if (BIT(21))
    LSBase = state->Base ;
 cpab = (state->LDC[CPNum])(state,ARMul_DATA,instr,data) ;
 while (cpab == ARMul_INC) {
    address += 4 ;
    data = ARMul_LoadWordN(state,address) ;
    cpab = (state->LDC[CPNum])(state,ARMul_DATA,instr,data) ;
    }
 if (state->abortSig || state->Aborted) {
    TAKEABORT ;
    }
 }

/***************************************************************************\
* This function does the work of generating the addresses used in an        *
* STC instruction.  The code here is always post-indexed, it's up to the    *
* caller to get the input address correct and to handle base register       *
* modification. It also handles the Busy-Waiting.                           *
\***************************************************************************/

void ARMul_STC(ARMul_State *state,ARMword instr,ARMword address)
{unsigned cpab ;
 ARMword data ;

 UNDEF_LSCPCBaseWb ;
 if (ADDREXCEPT(address) || VECTORACCESS(address)) {
    INTERNALABORT(address) ;
    }
 cpab = (state->STC[CPNum])(state,ARMul_FIRST,instr,&data) ;
 while (cpab == ARMul_BUSY) {
    ARMul_Icycles(state,1,0) ;
    if (IntPending(state)) {
       cpab = (state->STC[CPNum])(state,ARMul_INTERRUPT,instr,0) ;
       return ;
       }
    else
       cpab = (state->STC[CPNum])(state,ARMul_BUSY,instr,&data) ;
    }
 if (cpab == ARMul_CANT) {
    CPTAKEABORT ;
    return ;
    }
#ifndef MODE32
 if (ADDREXCEPT(address) || VECTORACCESS(address)) {
    INTERNALABORT(address) ;
    }
#endif
 BUSUSEDINCPCN ;
 if (BIT(21))
    LSBase = state->Base ;
 cpab = (state->STC[CPNum])(state,ARMul_DATA,instr,&data) ;
 ARMul_StoreWordN(state,address,data) ;
 while (cpab == ARMul_INC) {
    address += 4 ;
    cpab = (state->STC[CPNum])(state,ARMul_DATA,instr,&data) ;
    ARMul_StoreWordN(state,address,data) ;
    }
 if (state->abortSig || state->Aborted) {
    TAKEABORT ;
    }
 }

/***************************************************************************\
*        This function does the Busy-Waiting for an MCR instruction.        *
\***************************************************************************/

void ARMul_MCR(ARMul_State *state,ARMword instr, ARMword source)
{unsigned cpab ;

 cpab = (state->MCR[CPNum])(state,ARMul_FIRST,instr,source) ;
 while (cpab == ARMul_BUSY) {
    ARMul_Icycles(state,1,0) ;
    if (IntPending(state)) {
       cpab = (state->MCR[CPNum])(state,ARMul_INTERRUPT,instr,0) ;
       return ;
       }
    else
       cpab = (state->MCR[CPNum])(state,ARMul_BUSY,instr,source) ;
    }
 if (cpab == ARMul_CANT)
    ARMul_Abort(state,ARMul_UndefinedInstrV) ;
 else {
    BUSUSEDINCPCN ;
    ARMul_Ccycles(state,1,0) ;
    }
 }

/***************************************************************************\
*        This function does the Busy-Waiting for an MRC instruction.        *
\***************************************************************************/

ARMword ARMul_MRC(ARMul_State *state,ARMword instr)
{unsigned cpab ;
 ARMword result = 0 ;

 cpab = (state->MRC[CPNum])(state,ARMul_FIRST,instr,&result) ;
 while (cpab == ARMul_BUSY) {
    ARMul_Icycles(state,1,0) ;
    if (IntPending(state)) {
       cpab = (state->MRC[CPNum])(state,ARMul_INTERRUPT,instr,0) ;
       return(0) ;
       }
    else
       cpab = (state->MRC[CPNum])(state,ARMul_BUSY,instr,&result) ;
    }
 if (cpab == ARMul_CANT) {
    ARMul_Abort(state,ARMul_UndefinedInstrV) ;
    result = ECC ; /* Parent will destroy the flags otherwise */
    }
 else {
    BUSUSEDINCPCN ;
    ARMul_Ccycles(state,1,0) ;
    ARMul_Icycles(state,1,0) ;
    }
 return(result) ;
}

/***************************************************************************\
*        This function does the Busy-Waiting for an CDP instruction.        *
\***************************************************************************/

void ARMul_CDP(ARMul_State *state,ARMword instr)
{unsigned cpab ;

 cpab = (state->CDP[CPNum])(state,ARMul_FIRST,instr) ;
 while (cpab == ARMul_BUSY) {
    ARMul_Icycles(state,1,0) ;
    if (IntPending(state)) {
       cpab = (state->CDP[CPNum])(state,ARMul_INTERRUPT,instr) ;
       return ;
       }
    else
       cpab = (state->CDP[CPNum])(state,ARMul_BUSY,instr) ;
    }
 if (cpab == ARMul_CANT)
    ARMul_Abort(state,ARMul_UndefinedInstrV) ;
 else
    BUSUSEDN ;
}

/***************************************************************************\
*      This function handles Undefined instructions, as CP isntruction      *
\***************************************************************************/

void ARMul_UndefInstr(ARMul_State *state,ARMword instr)
{
 ARMul_Abort(state,ARMul_UndefinedInstrV) ;
}

/***************************************************************************\
*           Return TRUE if an interrupt is pending, FALSE otherwise.        *
\***************************************************************************/

unsigned IntPending(ARMul_State *state)
{
 if (state->Exception) { /* Any exceptions */
    if (state->NresetSig == LOW) {
       ARMul_Abort(state,ARMul_ResetV) ;
       return(TRUE) ;
       }
    else if (!state->NfiqSig && !FFLAG) {
       ARMul_Abort(state,ARMul_FIQV) ;
       return(TRUE) ;
       }
    else if (!state->NirqSig && !IFLAG) {
       ARMul_Abort(state,ARMul_IRQV) ;
       return(TRUE) ;
       }
    }
 return(FALSE) ;
 }

/***************************************************************************\
*               Align a word access to a non word boundary                  *
\***************************************************************************/

ARMword ARMul_Align(ARMul_State *state, ARMword address, ARMword data)
{/* this code assumes the address is really unaligned,
    as a shift by 32 is undefined in C */

 address = (address & 3) << 3 ; /* get the word address */
 return( ( data >> address) | (data << (32 - address)) ) ; /* rot right */
}

/***************************************************************************\
* This routine is used to call another routine after a certain number of    *
* cycles have been executed. The first parameter is the number of cycles    *
* delay before the function is called, the second argument is a pointer     *
* to the function. A delay of zero doesn't work, just call the function.    *
\***************************************************************************/

void ARMul_ScheduleEvent(ARMul_State *state, unsigned long delay, unsigned (*what)())
{unsigned long when ;
 struct EventNode *event ;

 if (state->EventSet++ == 0)
    state->Now = ARMul_Time(state) ;
 when = (state->Now + delay) % EVENTLISTSIZE ;
 event = (struct EventNode *)malloc(sizeof(struct EventNode)) ;
 event->func = what ;
 event->next = *(state->EventPtr + when) ;
 *(state->EventPtr + when) = event ;
}

/***************************************************************************\
* This routine is called at the beginning of every cycle, to envoke         *
* scheduled events.                                                         *
\***************************************************************************/

void ARMul_EnvokeEvent(ARMul_State *state)
{static unsigned long then ;

 then = state->Now ;
 state->Now = ARMul_Time(state) % EVENTLISTSIZE ;
 if (then < state->Now) /* schedule events */
    EnvokeList(state,then,state->Now) ;
 else if (then > state->Now) { /* need to wrap around the list */
    EnvokeList(state,then,EVENTLISTSIZE-1L) ;
    EnvokeList(state,0L,state->Now) ;
    }
 }

static void EnvokeList(ARMul_State *state, unsigned long from, unsigned long to)
/* envokes all the entries in a range */
{struct EventNode *anevent ;

 for (; from <= to ; from++) {
    anevent = *(state->EventPtr + from) ;
    while (anevent) {
       (anevent->func)(state) ;
       state->EventSet-- ;
       anevent = anevent->next ;
       }
    *(state->EventPtr + from) = NULL ;
    }
 }

/***************************************************************************\
* This routine is returns the number of clock ticks since the last reset.   *
\***************************************************************************/

unsigned long ARMul_Time(ARMul_State *state)
{return(state->NumScycles + state->NumNcycles +
        state->NumIcycles + state->NumCcycles + state->NumFcycles) ;
}