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/* m88k.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.
*/
/* Callee-save r14..r25, r31(sp), r30(fp). r1 === return pc.
* Argument registers r2..r9, return value r2..r3.
*
* On startup, restore regs so retpc === call to a function to start.
*
* We're going to call a function (r2) from within the context switch
* routine. Call it on the new thread's stack on behalf of the old
* thread.
*/
.globl _qt_block
.globl _qt_blocki
.globl _qt_abort
.globl _qt_start
.globl _qt_vstart
/*
** r2: ptr to function to call once curr is suspended
** and control is on r5's stack.
** r3: 1'th arg to *r2.
** r4: 2'th arg to *r2.
** r5: sp of thread to suspend.
**
** The helper routine returns a value that is passed on as the
** return value from the blocking routine. Since we don't
** touch r2 between the helper's return and the end of
** function, we get this behavior for free.
**
** Same entry for integer-only and floating-point, since there
** are no separate integer and floating-point registers.
**
** Each procedure call sets aside a ``home region'' of 8 regs
** for r2-r9 for varargs. For context switches we don't use
** the ``home region'' for varargs so use it to save regs.
** Allocate 64 bytes of save space -- use 32 bytes of register
** save area passed in to us plus 32 bytes we allcated, use
** the other 32 bytes for save area for a save area to call
** the helper function.
*/
_qt_block:
_qt_blocki:
sub r31, r31,64 /* Allocate reg save space. */
st r1, r31,8+32 /* Save callee-save registers. */
st r14, r31,12+32
st.d r15, r31,16+32
st.d r17, r31,24+32
st.d r19, r31,32+32
st.d r21, r31,40+32
st.d r23, r31,48+32
st r25, r31,56+32
st r30, r31,60+32
_qt_abort:
addu r14, r31,0 /* Remember old sp. */
addu r31, r5,0 /* Set new sp. */
jsr.n r2 /* Call helper. */
addu r2, r14,0 /* Pass old sp as an arg0 to helper. */
ld r1, r31,8+32 /* Restore callee-save registers. */
ld r14, r31,12+32
ld.d r15, r31,16+32
ld.d r17, r31,24+32
ld.d r19, r31,32+32
ld.d r21, r31,40+32
ld.d r23, r31,48+32
ld r25, r31,56+32
ld r30, r31,60+32
jmp.n r1 /* Return to new thread's caller. */
addu r31, r31,64 /* Free register save space. */
/*
** Non-varargs thread startup.
** See `m88k.h' for register use conventions.
*/
_qt_start:
addu r2, r14,0 /* Set user arg `pu'. */
addu r3, r15,0 /* ... user function pt. */
jsr.n r17 /* Call `only'. */
addu r4, r16,0 /* ... user function userf. */
bsr _qt_error /* `only' erroniously returned. */
/*
** Varargs thread startup.
** See `m88k.h' for register use conventions.
**
** Call the `startup' function with just argument `pt'.
** Then call `vuserf' with 8 register args plus any
** stack args.
** Then call `cleanup' with `pt' and the return value
** from `vuserf'.
*/
_qt_vstart:
addu r18, r30,0 /* Remember arg7 to `vuserf'. */
addu r30, r0,0 /* Null-terminate call chain. */
jsr.n r17 /* Call `startup'. */
addu r2, r15,0 /* `pt' is arg0 to `startup'. */
addu r2, r19,0 /* Set arg0. */
addu r3, r20,0 /* Set arg1. */
addu r4, r21,0 /* Set arg2. */
addu r5, r22,0 /* Set arg3. */
addu r6, r23,0 /* Set arg4. */
addu r7, r24,0 /* Set arg5. */
addu r8, r25,0 /* Set arg6. */
jsr.n r16 /* Call `vuserf'. */
addu r9, r18,0 /* Set arg7. */
addu r3, r2,0 /* Ret. value is arg1 to `cleanup'. */
jsr.n r14 /* Call `cleanup'. */
addu r2, r15,0 /* `pt' is arg0 to `cleanup'. */
bsr _qt_error /* `cleanup' erroniously returned. */
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