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/*
* Creation Date: <2001/01/26 21:21:53 samuel>
* Time-stamp: <2001/06/21 14:27:35 samuel>
*
* <mainloop.S>
*
* Main loop
*
* Copyright (C) 2000, 2001 Samuel Rydh (samuel@ibrium.se)
*
* 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
*
*/
#include "mol_config.h"
#include "rvec.h"
#include "multiplexer.h"
#include "processor.h"
#include "asm_offsets.h"
#include "asmdefs.h"
#include "mac_registers.h"
//#define DEBUG
//#define DEBUG_REGISTERS // Always save gprs/fprs
////////////////////////////////////////////////////////////////////////
//
// This file depends upon the register conventions of the platform.
// Linux/PPC uses the System V ABI:
//
// Altered by function calls:
// r0,r3-r12,(r2 ?)
// fr0-fr13
// cr[0,1,5,6,7]
// ctr
// xer
// certain bits of fpscr
//
// Not altered by function calls:
// r13-r31
// cr[2,3,4]
// fr14-fr31
// certain bits of fpscr
//
// The AltiVec implementation makes the assumption that *NO*
// altivec registers (including VRSAVE) is touched except by us.
//
////////////////////////////////////////////////////////////////////////
/************************************************************************/
/* DEBUG */
/************************************************************************/
.macro DBG_ASSERT_RVF_BIT bit scr
#ifdef DEBUG
lwz \scr,STACK_DBG_RVEC(r1)
rlwinm \scr,\scr,0,\bit,\bit
beq error_detected
#endif
.endm
#ifdef DEBUG
.print "**************** DEBUG ENABLED IN mainloop_asm.S ***************"
error_detected:
li r3,RVEC_INTERNAL_ERROR
lwz r4,STACK_DBG_RVEC(r1)
b do_rvec_jump
#endif
.macro DEBUG_IN_KERNEL val, scr1, scr2
#ifdef DEBUG
lwz \scr1,STACK_MREGS(r1)
li \scr2,\val
stw \scr2,xDBG_IN_MAC_MODE(\scr1)
#endif
.endm
/************************************************************************/
/* MACROS */
/************************************************************************/
.macro SETVEC, name, rvec, func, scr, scr2
bl 1f
.ascii "\name\0"
.balign 4,0
1:
LOADI \scr,gRVECtable
LOADI \scr2,\func
stw \scr2,((\rvec & RVEC_MASK) * RVEC_ESIZE) (\scr)
mflr \scr2
stw \scr2,((\rvec & RVEC_MASK) * RVEC_ESIZE + 8) (\scr)
.endm
/************************************************************************/
/* mainloop_asm_init */
/************************************************************************/
// This could be done in C, but we do it here for the sake
// of modularity.
GLOBL( mainloop_asm_init ):
mflr r5
SETVEC "Init -", RVEC_INITIALIZE, rvec_initialize, /**/ r3,r4
SETVEC "NOP -", RVEC_NOP, loop, /**/ r3,r4
SETVEC "Exit -", RVEC_EXIT, mainloop_out, /**/ r3,r4
SETVEC "EnableFPU -", RVEC_ENABLE_FPU, rvec_enable_fpu, /**/ r3,r4
SETVEC "EnableAltivec -", RVEC_ENABLE_ALTIVEC, rvec_enable_altivec, /**/ r3,r4
mtlr r5
blr
/************************************************************************/
/* mainloop */
/************************************************************************/
///////////////////////////////////////////////////////////////
// mainloop( rvec, mregs, session_magic )
// The following registers hold mac-values:
//
// r13-r31
// fr0-fr12 (if fpu_state == FPU_DIRTY)
// fr14-fr31
//
// In particular, fr13 and fpscr *never* hold mac values.
// (We can't touch fpscr since that might trigger a FPU exception)
.set STACK_SPACE, 416
.set STACK_LR, STACK_SPACE+4
.set STACK_RESERVED, 0 // 8 bytes
.set STACK_DUMMY_FP, 8 // 8 bytes
.set STACK_MREGS, 16 // 4 bytes
#ifdef DEBUG
.set STACK_DBG_RVEC, 20 // 4 bytes
#endif
.set STACK_SESSION_MAGIC, 24 // 4 bytes
.set STACK_FPRS, 32 // 256 bytes
.set STACK_GPRS, 288 // 128 bytes
GLOBL( mainloop ):
// Push stackframe
stwu r1,-STACK_SPACE(r1)
mflr r0
mfxer r11 // XER (uncertain about this one)
mfcr r12 // CR (cr1-cr7 needs to be saved?)
mffs fr3
stfd fr3,xEMULATOR_FPSCR-4(r1) // Save emulator fpscr
STORE_GPR_RANGE r11,r31,STACK_GPRS,r1 // don't touch r13-r31 (and f14-f31)
STORE_GPR_RANGE r2,r2,STACK_GPRS,r1 // probably not necessary
STORE_FPR_RANGE fr14,fr31,STACK_FPRS,r1 // don't touch fp14-fp31
stw r0,STACK_LR(r1)
stw r4,STACK_MREGS(r1)
stw r5,STACK_SESSION_MAGIC(r1)
lwz r11,xALTIVEC_USED(r4) // Only touch the AltiVec unit if we know
cmpwi r11,0 // we have one.
beq 1f
xVEC_LOAD r4, /**/ r11
1: xLOAD_FULL_FPU r4 // loads everything (except fr13 and fpscr)
xGPR_LOAD_RANGE 13,31,r4 // r4 = mbase
b do_rvec_jump
loop:
lwz r6,STACK_MREGS(r1)
lwz r7,xINTERRUPT(r6)
cmpwi r7,0
bne- mol_interrupt
li r4,MOL_ENTRY_R4_MAGIC
li r5,MOL_ENTRY_R5_MAGIC
// Any privileged instruction
switch_magic:
DEBUG_IN_KERNEL 1, /**/ r10,r11
lwz r7,STACK_SESSION_MAGIC(r1)
MOL_KERNEL_ENTRY_MAGIC // Only r1, r2 and rvec parameters are valid afterwards
DEBUG_IN_KERNEL 0, /**/ r10,r11
do_rvec_jump:
#ifdef DEBUG_REGISTERS
bl save_fpu
bl save_gprs
#endif
// Return point, r3=rvec#, r4+=arguments
rlwinm. r0,r3,0,RVF_fb,RVF_lb // Any RVEC flags?
bne- handle_rvec_flags // Mod r0,r9-r12
do_rvec_jump_:
LOADI r9,gRVECtable // Jump to return vector
rlwinm r10,r3, RVEC_ESIZE_LOG2, 31-(NRVECS_LOG2-1)-RVEC_ESIZE_LOG2, 31-RVEC_ESIZE_LOG2
lwzx r0,r9,r10
mtlr r0
#ifdef COLLECT_RVEC_STATISTICS
addi r10,r10,4
lwzx r11,r9,r10
addi r0,r11,1
stwx r0,r9,r10
#endif
#ifdef DEBUG
lwz r9,STACK_MREGS(r1)
stw r3,xDBG_LAST_RVEC(r9)
stw r3,STACK_DBG_RVEC(r1)
#endif
blrl
cmpwi r3,0
beq+ loop
mtcr r3 // Bit 0-3 (cr0) not used for flags
lwz r4,STACK_MREGS(r1)
btl- kRVecGPRsModifiedBit, gprs_modified
btl- kRVecFPRsModifiedBit, fprs_modified
bt- kRVecExitBit, mainloop_out
b loop
mol_interrupt:
li r3,RVEC_INTERRUPT
b do_rvec_jump
mainloop_out:
bl save_altivec // save altivec (for session-save/debug)
bl save_fpu // save fpu registers (if necessary)
lwz r4,STACK_MREGS(r1)
xGPR_SAVE_RANGE 13,31,r4 // save xGPR13-xGPR31
// Pop stackframe
lwz r0,STACK_LR(r1)
LOAD_GPR_RANGE r11,r31,STACK_GPRS,r1
LOAD_FPR_RANGE fr14,fr31,STACK_FPRS,r1
mtxer r11
mtcr r12
mtlr r0
addi r1,r1,STACK_SPACE
blr
/////////////////////////////////////////////////////////////////
// kernel_call_return
//
// r3 RVEC number
//
// If our low-level asm kernel code calls C-kernel code directly,
// then the return point is set to kernel_call_return rather than
// do_rvec_jump. This allows the C-kernel code to pass parameters
// to rvec functions by storing them in xRVEC_PARAM.
kernel_call_return:
lwz r8,STACK_MREGS(r1)
lwz r4,xRVEC_PARAM0(r8)
lwz r5,xRVEC_PARAM1(r8)
lwz r6,xRVEC_PARAM2(r8)
b do_rvec_jump
////////////////////////////////////////////////////////////////
// handle_rvec_flags
//
// r0 flags (upper 16 bits; top 4 bits unused)
// r3-rX rvec call
//
// safe to modify: r0, r9-r12
handle_rvec_flags:
mtcr r0
btl RVF_USES_FPRS_BIT, save_fpu // should go before RVF_FPU_UNSAFE_VECTOR
btl RVF_FPU_UNSAFE_BIT, save_low_fpu
btl RVF_USES_GPRS_BIT, save_gprs
b do_rvec_jump_
// Make sure the complete FPU is stored in mregs
// Modifies r9-r11
save_fpu:
lwz r10,STACK_MREGS(r1)
lwz r9,xFPU_STATE(r10)
cmpwi r9,FPU_STATE_SAVED // If the FPU is already saved, do nothing
beqlr+
li r11,FPU_STATE_SAVED
stw r11,xFPU_STATE(r10)
crclr RVF_FPU_UNSAFE_BIT
xSAVE_TOPHALF_FPU r10 // Save top half of the FPU
cmpwi r9,FPU_STATE_DIRTY // and the lower half of FPU if its dirty
bnelr
xSAVE_LOW_FPU r10 // save all of the FPU
blr
// Save low FPU registers (if the FPU is dirty). We must do this before
// taking a vector that might touch the FPU.
// Modifies r9-r11
save_low_fpu:
lwz r10,STACK_MREGS(r1)
lwz r9,xFPU_STATE(r10)
cmpwi r9,FPU_STATE_DIRTY // Save FPU if its dirty
bnelr+
li r11,FPU_STATE_HALF_SAVED
xSAVE_LOW_FPU r10 // r10 = mregs
stw r11,xFPU_STATE(r10)
blr
// Make sure all GPRs are stored in mregs
save_gprs:
lwz r10,STACK_MREGS(r1)
xGPR_SAVE_RANGE 13,31,r10 // r10=mregs, save xGPR13-xGPR31
blr
save_altivec:
lwz r10,STACK_MREGS(r1)
lwz r9,xALTIVEC_USED(r10)
cmpwi r9,0
beqlr
xVEC_SAVE r10, /**/ r9
blr
///////////////////////////////////////////////////////////////////
// rvec return flags
//
// r3: return code
// r4: mregs
//
// Safe to modify: r0,r5-r12, lr, ctr
// called if kRVecGPRsModified was return by the rvector
gprs_modified:
DBG_ASSERT_RVF_BIT RVF_USES_GPRS_BIT, /**/ r12
xGPR_LOAD_RANGE 13,31,r4 // r4 = mbase
blr
// called kRVecFPRsModified was return by the rvector
fprs_modified:
DBG_ASSERT_RVF_BIT RVF_USES_FPRS_BIT, /**/ r12
xLOAD_TOPHALF_FPU r4 // we only need to reload the top half of the fpu.
blr
/************************************************************************/
/* Miscellaneous rvecs */
/************************************************************************/
rvec_initialize:
LOADI r6,kernel_call_return
li r4,MOL_INITIALIZE_R4_MAGIC
li r5,MOL_INITIALIZE_R5_MAGIC
b switch_magic
rvec_enable_fpu:
stfd fr0,STACK_DUMMY_FP(r1) // enable the fpu
b loop
rvec_enable_altivec:
li r3,1
lwz r4,STACK_MREGS(r1)
stw r3,xALTIVEC_USED(r4) // Useful for AltiVec detection
.long 0x10000484 // vor v0,v0,v0
b loop
|
