1; pa-risc.s -- assembly support.
2
3; QuickThreads -- Threads-building toolkit.
4; Copyright (c) 1993 by David Keppel
5;
6; Permission to use, copy, modify and distribute this software and
7; its documentation for any purpose and without fee is hereby
8; granted, provided that the above copyright notice and this notice
9; appear in all copies.  This software is provided as a
10; proof-of-concept and for demonstration purposes; there is no
11; representation about the suitability of this software for any
12; purpose.
13
14; This file (pa-risc.s) is part of the port of QuickThreads for
15; PA-RISC 1.1 architecture.  This file implements context switches
16; and thread startup.  It was written in 1994 by Uwe Reder
17; (`uereder@cip.informatik.uni-erlangen.de') for the Operating
18; Systems Department (IMMD4) at the University of Erlangen/Nuernberg
19; Germany.
20
21
22; Callee saves general registers gr3..gr18,
23;              floating-point registers fr12..fr21.
24
25            .CODE
26
27            .IMPORT $$dyncall, MILLICODE
28            .IMPORT qt_error, CODE
29
30            .EXPORT qt_blocki, ENTRY
31            .EXPORT qt_block, ENTRY
32            .EXPORT qt_abort, ENTRY
33            .EXPORT qt_start, ENTRY
34            .EXPORT qt_vstart, ENTRY
35
36
37; arg0: ptr to function (helper) to call once curr is suspended
38;       and control is on arg3's stack.
39; arg1: 1'th arg to *arg0.
40; arg2: 2'th arg to *arg0.
41; arg3: sp of new thread.
42
43qt_blocki
44            .PROC
45            .CALLINFO   CALLER, FRAME=0, SAVE_RP, ENTRY_GR=18
46            .ENTRY
47
48            stw         %rp,-20(%sp)    ; save rp to old frame-marker
49
50            stwm        %r3,128(%sp)    ; save callee-saves general registers
51            stw         %r4,-124(%sp)
52            stw         %r5,-120(%sp)
53            stw         %r6,-116(%sp)
54            stw         %r7,-112(%sp)
55            stw         %r8,-108(%sp)
56            stw         %r9,-104(%sp)
57            stw         %r10,-100(%sp)
58            stw         %r11,-96(%sp)
59            stw         %r12,-92(%sp)
60            stw         %r13,-88(%sp)
61            stw         %r14,-84(%sp)
62            stw         %r15,-80(%sp)
63            stw         %r16,-76(%sp)
64            stw         %r17,-72(%sp)
65            stw         %r18,-68(%sp)
66
67qt_abort
68            copy        %arg0,%r22      ; helper to be called by $$dyncall
69            copy        %sp,%arg0       ; pass current sp as arg0 to helper
70            copy        %arg3,%sp       ; set new sp
71
72            .CALL
73            bl          $$dyncall,%mrp  ; call helper
74            copy        %mrp,%rp
75
76            ldw         -68(%sp),%r18   ; restore general registers
77            ldw         -72(%sp),%r17
78            ldw         -76(%sp),%r16
79            ldw         -80(%sp),%r15
80            ldw         -84(%sp),%r14
81            ldw         -88(%sp),%r13
82            ldw         -92(%sp),%r12
83            ldw         -96(%sp),%r11
84            ldw         -100(%sp),%r10
85            ldw         -104(%sp),%r9
86            ldw         -108(%sp),%r8
87            ldw         -112(%sp),%r7
88            ldw         -116(%sp),%r6
89            ldw         -120(%sp),%r5
90            ldw         -124(%sp),%r4
91
92            ldw         -148(%sp),%rp   ; restore return-pointer
93
94            bv          %r0(%rp)        ; return to caller
95            ldwm        -128(%sp),%r3
96
97            .EXIT
98            .PROCEND
99
100
101qt_block
102            .PROC
103            .CALLINFO   CALLER, FRAME=0, SAVE_RP, ENTRY_FR=21
104            .ENTRY
105
106            stw         %rp,-20(%sp)    ; save rp to old frame-marker
107
108            fstds,ma    %fr12,8(%sp)    ; save callee-saves float registers
109            fstds,ma    %fr13,8(%sp)
110            fstds,ma    %fr14,8(%sp)
111            fstds,ma    %fr15,8(%sp)
112            fstds,ma    %fr16,8(%sp)
113            fstds,ma    %fr17,8(%sp)
114            fstds,ma    %fr18,8(%sp)
115            fstds,ma    %fr19,8(%sp)
116            fstds,ma    %fr20,8(%sp)
117            fstds,ma    %fr21,8(%sp)
118
119            .CALL
120            bl          qt_blocki,%rp
121            ldo         48(%sp),%sp
122
123            ldo         -48(%sp),%sp
124
125            fldds,mb    -8(%sp),%fr21   ; restore callee-saves float registers
126            fldds,mb    -8(%sp),%fr20
127            fldds,mb    -8(%sp),%fr19
128            fldds,mb    -8(%sp),%fr18
129            fldds,mb    -8(%sp),%fr17
130            fldds,mb    -8(%sp),%fr16
131            fldds,mb    -8(%sp),%fr15
132            fldds,mb    -8(%sp),%fr14
133            fldds,mb    -8(%sp),%fr13
134
135            ldw         -28(%sp),%rp    ; restore return-pointer
136
137            bv          %r0(%rp)        ; return to caller.
138            fldds,mb    -8(%sp),%fr12
139
140            .EXIT
141            .PROCEND
142
143
144qt_start
145            .PROC
146            .CALLINFO   CALLER, FRAME=0
147            .ENTRY
148
149            copy        %r18,%arg0      ; set user arg `pu'.
150            copy        %r17,%arg1      ; ... user function pt.
151            copy        %r16,%arg2      ; ... user function userf.
152                                        ; %r22 is a caller-saves register
153            copy        %r15,%r22       ; function to be called by $$dyncall
154
155            .CALL                       ; in=%r22
156            bl          $$dyncall,%mrp  ; call `only'.
157            copy        %mrp,%rp
158
159            bl,n        qt_error,%r0    ; `only' erroniously returned.
160
161            .EXIT
162            .PROCEND
163
164
165; Varargs
166;
167; First, call `startup' with the `pt' argument.
168;
169; Next, call the user's function with all arguments.
170; We don't know whether arguments are integers, 32-bit floating-points or
171; even 64-bit floating-points, so we reload all the registers, possibly
172; with garbage arguments.  The thread creator provided non-garbage for
173; the arguments that the callee actually uses, so the callee never gets
174; garbage.
175;
176;            -48    -44    -40    -36    -32
177;             | arg3 | arg2 | arg1 | arg0 |
178;             -----------------------------
179; integers:     arg3   arg2   arg1   arg0
180; 32-bit fps:  farg3  farg2  farg1  farg0
181; 64-bit fps:  <---farg3-->  <---farg1-->
182;
183; Finally, call `cleanup' with the `pt' argument and with the return value
184; from the user's function.  It is an error for `cleanup' to return.
185
186qt_vstart
187            .PROC
188            .CALLINFO   CALLER, FRAME=0
189            .ENTRY
190
191            ; Because the startup function may damage the fixed arguments
192            ; on the stack (PA-RISC Procedure Calling Conventions Reference
193            ; Manual, 2.4 Fixed Arguments Area), we allocate a seperate
194            ; stack frame for it.
195            ldo         64(%sp),%sp
196
197            ; call: void startup(void *pt)
198
199            copy        %r15,%arg0      ; `pt' is arg0 to `startup'.
200            copy        %r16,%r22
201            .CALL
202            bl          $$dyncall,%mrp  ; Call `startup'.
203            copy        %mrp,%rp
204
205            ldo         -64(%sp),%sp
206
207            ; call: void *qt_vuserf_t(...)
208
209            ldw         -36(%sp),%arg0  ; Load args to integer registers.
210            ldw         -40(%sp),%arg1
211            ldw         -44(%sp),%arg2
212            ldw         -48(%sp),%arg3
213            ; Index of fld[w|d]s only ranges from -16 to 15, so we
214            ; take r22 to be our new base register.
215            ldo         -32(%sp),%r22
216            fldws       -4(%r22),%farg0 ; Load args to floating-point registers.
217            fldds       -8(%r22),%farg1
218            fldws       -12(%r22),%farg2
219            fldds       -16(%r22),%farg3
220            copy        %r17,%r22
221            .CALL
222            bl          $$dyncall,%mrp  ; Call `userf'.
223            copy        %mrp,%rp
224
225            ; call: void cleanup(void *pt, void *vuserf_return)
226
227            copy        %r15,%arg0      ; `pt' is arg0 to `cleanup'.
228            copy        %ret0,%arg1     ; Return-value is arg1 to `cleanup'.
229            copy        %r18,%r22
230            .CALL
231            bl          $$dyncall,%mrp  ; Call `cleanup'.
232            copy        %mrp,%rp
233
234            bl,n        qt_error,%r0
235
236            .EXIT
237            .PROCEND
238