/* powerpc-sys5.s -- assembly support. */
/*
* QuickThreads -- Threads-building toolkit.
* Copyright (c) 1993 by David Keppel
*
* Permission to use, copy, modify and distribute this software and
* its documentation for any purpose and without fee is hereby
* granted, provided that the above copyright notice and this notice
* appear in all copies. This software is provided as a
* proof-of-concept and for demonstration purposes; there is no
* representation about the suitability of this software for any
* purpose.
* PowerPC-System V thread switching module.
*
* This software is largely based on the original PowerPC-Linux porting
* developed by Ken Aaker <kenaaker@silverbacksystems.com>
*
* Marco Bucci <marco.bucci@inwind.it>
* December 2002
*
*/
/*
*
* PowerPC Register convections:
*
* r0 volatile
* r1 SP
* r2 system reserved
* r3-r4 volatile for parameter passing and function return
* r5-r10 volatile for parameter passing
* r11-r12 volatile
* r13-r14 non volatile registers
* f0 volatile
* f1 volatile for parameter passing and function return
* f2-f13 volatile for parameter passing
* f14-f31 non volatile
*
* cr2-cr4 non volatile
*
*
* See on the heather file for more documentation.
*
*
*
* IMPLEMENTATION NOTES
*
*
* 1) Condition register saving
* On most machines, the condition code register is caller-save.
* On the PPC, the condition code register is callee-save, so the
* thread context switch must preserve it.
*
*
* 2) Floating point registers saving
* On resuming a thread, floating point registers are or not restored just
* depending on which block routine suspended the thread (i.e. regardless
* whether "qt_block", "qt_blocki" or "qt_abort" is used to resume it).
* This behaviour is obtained by implementing "qt_block" by means af a nested
* call to "qt_blocki". As a result, the blocking of a thread always goes
* and returns through "qt_blocki and, if a thread was blocked by "qt_block",
* its execution resumes from the floating point restoring code on exit
* of "qt_block".
*
* Thanks to David Keppel that explained me this "simple" trick.
*
*
* 3) C languace code debugging
* The original version of this software was developed and debugged under
* MacOS X using the Metrowerks Code Warrior PPC integrated assembler.
* It could be still used with a C inline assembler by means of a suitable
* file to include it.
* In order to avoid "copy and paste" bugs, and make easyer the maintaining,
* I made the minimal changes, so you can find some strange code as:
*
* #if 0
* .if 0
* C code here
* .endif
* #endif
*
* This is just to embed some C code that is needed by the Code Warrior
* integrated assembler.
*
*
* 4) Assembly constants generation
* Constants used in the assembly code are generated by running
* the C code in the sequel (commented). It uses the C macros declared in
* the C heather in order to guarantee that the C interface and the assebly
* code are "aligned". I avoided the use of an assebler preprocessor since
* they are not so standard and moreover using macro espressions makes the
* assembly debugging more difficult.
*
*
#include <iostream>
#include "powerpc_sys5.h"
int main()
{
using namespace std;
int i;
cout << ".set LR_SAVE, " << PPC_LR_SAVE << endl;
cout << ".set BLOCKI_FSIZE, " << QUICKTHREADS_BLOCKI_FRAME_SIZE << endl;
cout << ".set BLOCKI_CR_SAVE, " << QUICKTHREADS_BLOCKI_CR_SAVE << endl;
cout << ".set BLOCK_FSIZE, " << QUICKTHREADS_BLOCK_FRAME_SIZE << endl;
cout << endl;
for(i=0; i<12; i++)
cout << ".set PAR_" << i << ", " << PPC_PAR(i) << endl;
cout << endl;
i = 13;
cout << ".set GPR_SAVE_" << i << ", " << QUICKTHREADS_BLOCKI_GPR_SAVE(i) << endl;
cout << endl;
for(i=31; i>13; i--)
cout << ".set FPR_SAVE_" << i << ", " << QUICKTHREADS_BLOCK_FPR_SAVE(i) << endl;
cout << endl;
cout << ".set VARGS_BKOFF, " << QUICKTHREADS_VARGS_BKOFF << endl;
cout << endl << endl << endl;
for(i=31; i>13; i--)
cout << "\tstfd\tf" << i << ",FPR_SAVE_" << i << "(%r1)" << endl;
cout << endl;
for(i=31; i>13; i--)
cout << "\tlfd \tf" << i << ",FPR_SAVE_" << i << "(%r1)" << endl;
cout << endl << endl << endl;
return 0;
}
*
*
*
*/
#if 0
.text
.align 4
.globl qt_block
.globl _qt_block
.globl qt_blocki
.globl _qt_blocki
.globl qt_abort
.globl _qt_abort
.globl qt_start
.globl _qt_start
.globl qt_vstart
.globl _qt_vstart
.set LR_SAVE, 4
.set BLOCKI_FSIZE, 96
.set BLOCKI_CR_SAVE, 8 /* CR is saved into the callee's stack frame */
.set BLOCK_FSIZE, 160
.set PAR_0, 8
.set PAR_1, 12
.set PAR_2, 16
.set PAR_3, 20
.set PAR_4, 24
.set PAR_5, 28
.set PAR_6, 32
.set PAR_7, 36
.set PAR_8, 40
.set PAR_9, 44
.set PAR_10, 48
.set PAR_11, 52
.set GPR_SAVE_13, 20
.set FPR_SAVE_31, 152
.set FPR_SAVE_30, 144
.set FPR_SAVE_29, 136
.set FPR_SAVE_28, 128
.set FPR_SAVE_27, 120
.set FPR_SAVE_26, 112
.set FPR_SAVE_25, 104
.set FPR_SAVE_24, 96
.set FPR_SAVE_23, 88
.set FPR_SAVE_22, 80
.set FPR_SAVE_21, 72
.set FPR_SAVE_20, 64
.set FPR_SAVE_19, 56
.set FPR_SAVE_18, 48
.set FPR_SAVE_17, 40
.set FPR_SAVE_16, 32
.set FPR_SAVE_15, 24
.set FPR_SAVE_14, 16
/* various offsets used by "qt_varg" */
.set P_T, PAR_0
.set P_STARTUP, PAR_1
.set P_USERF, PAR_2
.set P_CLEANUP, PAR_3
/* the offset used to move back the linkage area to be adiacent to
* the variant argument list before calling "userf(...).
* Skip "t", "startup", "userf", "cleanup" and first
* 8 parameters (since they are passed via registers) */
.set VARGS_BKOFF, 48
/* location where "t" and "cleanup" are saved (with respect of
* the stack frame base) */
.set P_T_SAVE, -4
.set P_CLEANUP_SAVE, -8
#endif
/* Block the current thread saving all integer non volatile registers and
* start a new thread.
*/
#if 0
.if 0
#endif
void *qt_blocki (void *helper, void *a0, void *a1, void *newthread);
asm void *qt_blocki (void *helper, void *a0, void *a1, void *newthread)
{
#if 0
.endif
#endif
#if 0
qt_blocki:
_qt_blocki:
#endif
/* prolog code */
stwu %r1,-BLOCKI_FSIZE(%r1) /* allocate the stack frame */
mflr %r0 /* return addr in r0 */
mfcr %r11 /* CR in r11 */
stw %r0,LR_SAVE+BLOCKI_FSIZE(%r1) /* save return addr in the stack */
stw %r11,BLOCKI_CR_SAVE(%r1) /* save CR in the stack */
stmw %r13,GPR_SAVE_13(%r1) /* save non-volatile reg */
/* call helper(qt_t *old, void *a0, void *a1) */
mtlr %r3 /* "helper" addr in the link reg */
mr %r3,%r1 /* current thread (i.e. the SP) in arg "old" */
mr %r1,%r6 /* swap to the new thread (i.e. to its SP) */
blrl /* jump to "helper" */
/* the "helper" return value is returned (since r3 is not changed) */
/* epilog code: return to the new thread's "qt_blocki" caller */
lmw %r13,GPR_SAVE_13(%r1) /* restore non-volatile reg */
lwz %r0,LR_SAVE+BLOCKI_FSIZE(%r1) /* recover return addr */
lwz %r11,BLOCKI_CR_SAVE(%r1) /* recover CR */
mtlr %r0 /* return address in the link reg */
mtcr %r11 /* restore CR */
addi %r1,%r1,BLOCKI_FSIZE /* free the stack frame */
blr /* return */
#if 0
.if 0
#endif
}
#if 0
.endif
#endif
/* Abort the current thread and start a new thread.
*/
#if 0
.if 0
#endif
void qt_abort (void *helper, void *a0, void *a1, void *newthread);
asm void qt_abort (void *helper, void *a0, void *a1, void *newthread)
{
#if 0
.endif
#endif
#if 0
qt_abort:
_qt_abort:
#endif
/* prolog code */
/* there is no prolog. It will never come back */
/* call helper(qt_t *old, void *a0, void *a1) */
mtlr %r3 /* "helper" addr in the link reg */
mr %r1,%r6 /* swap to the new thread (i.e. to its SP) */
/* we don't need to set "old", we can pass just garbage. Actually, since r3
is not changed, "old" is set to "helper" (don't care) */
blrl /* call "helper" */
/* the "helper" return value is returned (since r3 is not changed) */
/* epilog code: return to the new thread's "qt_blocki" caller */
lmw %r13,GPR_SAVE_13(%r1) /* restore non-volatile reg */
lwz %r0,LR_SAVE+BLOCKI_FSIZE(%r1) /* recover return addr */
lwz %r11,BLOCKI_CR_SAVE(%r1) /* recover CR */
mtlr %r0 /* return address in the link reg */
mtcr %r11 /* restore CR */
addi %r1,%r1,BLOCKI_FSIZE /* free the stack frame */
blr /* return */
#if 0
.if 0
#endif
}
#if 0
.endif
#endif
/* Block the current thread saving all non volatile registers and start
* a new thread.
*/
#if 0
.if 0
#endif
void *qt_block (void *helper, void *a0, void *a1, void *newthread);
asm void *qt_block (void *helper, void *a0, void *a1, void *newthread)
{
#if 0
.endif
#endif
# if 0
qt_block:
_qt_block:
#endif
/* prolog code */
stwu %r1,-BLOCK_FSIZE(%r1) /* allocate the stack frame */
mflr %r0 /* return addr in r0 */
stw %r0,LR_SAVE+BLOCK_FSIZE(%r1) /* save return addr in the stack */
/* save non-volatile fp reg */
stfd %f31,FPR_SAVE_31(%r1)
stfd %f30,FPR_SAVE_30(%r1)
stfd %f29,FPR_SAVE_29(%r1)
stfd %f28,FPR_SAVE_28(%r1)
stfd %f27,FPR_SAVE_27(%r1)
stfd %f26,FPR_SAVE_26(%r1)
stfd %f25,FPR_SAVE_25(%r1)
stfd %f24,FPR_SAVE_24(%r1)
stfd %f23,FPR_SAVE_23(%r1)
stfd %f22,FPR_SAVE_22(%r1)
stfd %f21,FPR_SAVE_21(%r1)
stfd %f20,FPR_SAVE_20(%r1)
stfd %f19,FPR_SAVE_19(%r1)
stfd %f18,FPR_SAVE_18(%r1)
stfd %f17,FPR_SAVE_17(%r1)
stfd %f16,FPR_SAVE_16(%r1)
stfd %f15,FPR_SAVE_15(%r1)
stfd %f14,FPR_SAVE_14(%r1)
/* block the thread */
bl qt_blocki
/* the thread is going to be resumed */
/* restore non-volatile fp reg */
lfd %f31,FPR_SAVE_31(%r1)
lfd %f30,FPR_SAVE_30(%r1)
lfd %f29,FPR_SAVE_29(%r1)
lfd %f28,FPR_SAVE_28(%r1)
lfd %f27,FPR_SAVE_27(%r1)
lfd %f26,FPR_SAVE_26(%r1)
lfd %f25,FPR_SAVE_25(%r1)
lfd %f24,FPR_SAVE_24(%r1)
lfd %f23,FPR_SAVE_23(%r1)
lfd %f22,FPR_SAVE_22(%r1)
lfd %f21,FPR_SAVE_21(%r1)
lfd %f20,FPR_SAVE_20(%r1)
lfd %f19,FPR_SAVE_19(%r1)
lfd %f18,FPR_SAVE_18(%r1)
lfd %f17,FPR_SAVE_17(%r1)
lfd %f16,FPR_SAVE_16(%r1)
lfd %f15,FPR_SAVE_15(%r1)
lfd %f14,FPR_SAVE_14(%r1)
lwz %r0,LR_SAVE+BLOCK_FSIZE(%r1) /* recover return addr */
mtlr %r0 /* return address in the link reg */
addi %r1,%r1,BLOCK_FSIZE /* free the stack frame */
blr /* return */
#if 0
.if 0
#endif
}
#if 0
.endif
#endif
/* Start a single argument thread using parameters preloaded in the stack
* during thread initialization (see comments on stack initialization in the
* heather file).
*
* Executes:
*
* only(u, t, userf);
*/
#if 0
.if 0
#endif
void qt_start(void);
asm void qt_start(void)
{
#if 0
.endif
#endif
#if 0
qt_start:
_qt_start:
#endif
lwz %r3,PAR_0(%r1) /* "u" in r3 */
lwz %r4,PAR_1(%r1) /* "t" in r4 */
lwz %r5,PAR_2(%r1) /* "userf" in r5 */
lwz %r6,PAR_3(%r1) /* "only" in r6 */
mtlr %r6 /* "only" address in the link reg */
/* call only(u, t, userf) */
blrl /* jump to "only" */
/* error if it returns */
b qt_error
/* dead code (some inline asm "wants" the epilog, or they genetare it) */
blr
#if 0
.if 0
#endif
}
#if 0
.endif
#endif
/* Start a variant argument thread using parameters preloaded in the stack
* during thread initialization (see comments on stack initialization in the
* heather file).
*
* Executes:
*
* startup(t);
* userf_return = userf(...);
* cleanup(pt, userf_return);
*
***** Stack layout on start *****
backchain -> STACK BOTTOM (higher address)
+==========================+
backchain - 4 -> | |
+ LOCAL VARIABLES AREA +
..............
+ +
| |
+--------------------------+
| |
+ ALIGNMEBNT PAD +
..............
+ (if needed) +
| |
+--------------------------+
| | arg(n)
+ +
| |
+ VARIABLE ARGUMENT LIST +
..............
+ for userf call +
SP + PAR(5) -> | | arg(1)
+ +
SP + PAR(4) -> | | arg(0)
+--------------------------+
SP + PAR(3) -> | | cleanup par
+ +
SP + PAR(2) -> | | userf par
+ PARAMETER AREA +
SP + PAR(1) -> | | startup par
+ +
SP + PAR(0) -> | | t par
+--------------------------+
| |
+ LINKAGE AREA +
SP -> | |
+==========================+
STACK TOP (lower address)
Stack grows down
|
V
***** Stack layout before call userf *****
backchain -> STACK BOTTOM (higher address)
+==========================+
backchain - 4 -> | |
+ LOCAL VARIABLES AREA +
..............
+ +
| |
+--------------------------+
| |
+ ALIGNMEBNT PAD +
..............
+ (if needed) +
| |
+--------------------------+
| | arg(n)
+ +
| |
+ VARIABLE ARGUMENT LIST +
..............
+ for userf call +
SP + PAR(1) -> | | arg(1)
+ +
SP + PAR(0) -> | | arg(0)
+--------------------------+
| |
+ LINKAGE AREA +
SP -> | |
+==========================+
STACK TOP (lower address)
Stack grows down
|
V
* To call "userf(...)", the argument list must be adiacent to the linkage
* area. Instead of copy the argument list, we move back the linkage area
* (actually, we just increase the SP and copy the backchain). "t" and
* "cleanup" are saved in a local variable area in order to call
* cleanup(pt, userf_return).
*/
#if 0
.if 0
#endif
void qt_vstart(void);
asm void qt_vstart(void)
{
#if 0
.endif
#endif
#if 0
qt_vstart:
_qt_vstart:
#endif
/* NOTICE: the callee routines could save parameter registers in the caller's
* stack parameter area. We put "t" in PAR(0) in such a way, if startup(t)
* will save "t", it will be saved on the same location thus not delething
* any other parameter.
*/
/* since we will move back the linckage area (to make it adiacent to the
* parameter list), we need to save "t" and "cleanup". We have made room for
* this on the bottom of the stack frame. */
/* save parameters in the local variable area */
lwz %r11,0(%r1) /* get the backchain */
lwz %r3,P_T(%r1)
lwz %r4,P_CLEANUP(%r1)
stw %r3,P_T_SAVE(%r11) /* save "pt" */
stw %r4,P_CLEANUP_SAVE(%r11) /* save "cleanup" */
/* call startup(t) */
lwz %r5,P_STARTUP(%r1)
mtlr %r5
blrl /* call "startup" */
/* call userf(...) */
lwz %r11,0(%r1) /* reload backchain (r11 is volatile) */
lwz %r4,P_USERF(%r1) /* load "userf" */
mtlr %r4
/* first eight parameter of the variant list must be copyed in
* GPR3-GPR10. There is a four places offset due to "t", "startup",
* userf" and "cleanup" */
lwz %r3,PAR_4(%r1)
lwz %r4,PAR_5(%r1)
lwz %r5,PAR_6(%r1)
lwz %r6,PAR_7(%r1)
lwz %r7,PAR_8(%r1)
lwz %r8,PAR_9(%r1)
lwz %r9,PAR_10(%r1)
lwz %r10,PAR_11(%r1)
/* move the linkage area to be adiacent to the argument list */
stw %r11,VARGS_BKOFF(%r1) /* copy backchain */
addi %r1,%r1,VARGS_BKOFF /* move back the stack */
blrl /* call "userf" */
/* call qt_cleanup(void *pt, void *vuserf_return) */
lwz %r11,0(%r1) /* reload backchain (r11 is volatile) */
mr %r4,%r3 /* push "userf" return as 2nd parameter */
lwz %r3,P_T_SAVE(%r11) /* reload "pt" */
lwz %r5,P_CLEANUP_SAVE(%r11) /* reload "cleanup" */
mtlr %r5
blrl
b qt_error
/* dead code (some inline asm "wants" the epilog, or they genetare it) */
blr
#if 0
.if 0
#endif
}
#if 0
.endif
#endif