URL https://opencores.org/ocsvn/eco32/eco32/trunk

Subversion Repositories eco32

[/] [eco32/] [trunk/] [simtest/] [rom/] [romboot.s] - Blame information for rev 213

Go to most recent revision | Details | Compare with Previous | View Log


;
; romboot.s -- the ROM bootstrap
;
 
        .set    termbase,0xF0300000     ; terminal base address
        .set    diskbase,0xF0400000     ; disk base address
        .set    diskbuffer,0xF0480000   ; disk buffer address
        .set    virtbase,0xC0000000     ; base of kernel virtual addresses
        .set    virtboot,0xC0000000     ; where to start the bootstrap sector
        .set    stacktop,0xC0100000     ; where the stack is located
 
        .set    PSW,0
        .set    TLB_INDEX,1
        .set    TLB_ENTRY_HI,2
        .set    TLB_ENTRY_LO,3
        .set    TLB_ENTRIES,32
 
        .code
 
reset:
        j       start
 
interrupt:
        j       interrupt
 
miss:
        j       miss
 
start:
        mvts    $0,PSW                   ; disable interrupts and user mode
        mvts    $0,TLB_ENTRY_LO          ; invalidate all TLB entries
        add     $8,$0,virtbase           ; by impossible virtual page number
        add     $9,$0,$0
        add     $10,$0,TLB_ENTRIES
tlblp:
        mvts    $8,TLB_ENTRY_HI
        mvts    $9,TLB_INDEX
        tbwi
        add     $8,$8,0x1000            ; all entries must be different
        add     $9,$9,1
        bne     $9,$10,tlblp
        add     $29,$0,stacktop          ; set stack pointer
        add     $4,$0,signon             ; show sign-on message
        jal     mout
cmdlp:
        add     $4,$0,prompt             ; show prompt
        jal     mout
        jal     echo
        sub     $8,$2,0x0D              ; '<ret>'?
        beq     $8,$0,rcmdlp
        sub     $8,$2,'b'               ; 'b'?
        beq     $8,$0,boot
        add     $4,$0,'?'                ; unknown command
        jal     cout
rcmdlp:
        jal     crlf
        j       cmdlp
 
boot:
        jal     crlf
        add     $8,$0,diskbase           ; check if disk present
        add     $9,$0,1000000            ; retry count
boot1:
        ldw     $16,$8,0         ; get status
        and     $10,$16,0x20            ; check if disk ready
        bne     $10,$0,boot2             ; ready - exit loop
        sub     $9,$9,1
        bne     $9,$0,boot1              ; try again
        j       nodsk                   ; enough retries - error
boot2:
        ldw     $16,$8,12               ; check if capacity greater than 0
        beq     $16,$0,nodsk             ; no - report error
        add     $4,$0,dfmsg              ; say that we found a disk
        jal     mout
        add     $4,$16,$0                ; and how many sectors it has
        jal     wout
        add     $4,$0,sctmsg
        jal     mout
        add     $8,$0,diskbase           ; try to load the boot sector
        add     $9,$0,1                  ; sector count
        stw     $9,$8,4
        add     $9,$0,0                   ; first sector
        stw     $9,$8,8
        add     $9,$0,1                  ; start command
        stw     $9,$8,0
dskwt:
        ldw     $9,$8,0
        and     $9,$9,0x10              ; done?
        beq     $9,$0,dskwt
        ldw     $9,$8,0
        and     $9,$9,0x08              ; error?
        bne     $9,$0,dskerr
        add     $8,$0,diskbuffer ; copy sector
        add     $9,$0,virtboot
        add     $10,$0,512
dskcp:
        ldw     $11,$8,0
        stw     $11,$9,0
        add     $8,$8,4
        add     $9,$9,4
        sub     $10,$10,4
        bne     $10,$0,dskcp
        add     $8,$0,virtboot           ; signature present?
        ldbu    $9,$8,512-2
        sub     $9,$9,0x55
        bne     $9,$0,nosig
        ldbu    $9,$8,512-1
        sub     $9,$9,0xAA
        bne     $9,$0,nosig
        jalr    $8                      ; finally... lift off
        j       cmdlp                   ; in case we ever return to here
 
nodsk:
        add     $4,$0,dnfmsg             ; there is no disk
        jal     mout
        j       cmdlp
 
dskerr:
        add     $4,$0,demsg              ; disk error
        jal     mout
        j       cmdlp
 
nosig:
        add     $4,$0,nsgmsg             ; no signature
        jal     mout
        j       cmdlp
 
crlf:
        sub     $29,$29,4
        stw     $31,$29,0
        add     $4,$0,0x0D
        jal     cout
        add     $4,$0,0x0A
        jal     cout
        ldw     $31,$29,0
        add     $29,$29,4
        jr      $31
 
mout:
        sub     $29,$29,8
        stw     $31,$29,4
        stw     $16,$29,0
        add     $16,$4,$0
mout1:
        ldbu    $4,$16,0
        beq     $4,$0,mout2
        jal     cout
        add     $16,$16,1
        j       mout1
mout2:
        ldw     $16,$29,0
        ldw     $31,$29,4
        add     $29,$29,8
        jr      $31
 
wout:
        sub     $29,$29,8
        stw     $31,$29,4
        stw     $16,$29,0
        add     $16,$4,$0
        slr     $4,$16,16
        jal     hout
        add     $4,$16,$0
        jal     hout
        ldw     $16,$29,0
        ldw     $31,$29,4
        add     $29,$29,8
        jr      $31
 
hout:
        sub     $29,$29,8
        stw     $31,$29,4
        stw     $16,$29,0
        add     $16,$4,$0
        slr     $4,$16,8
        jal     bout
        add     $4,$16,$0
        jal     bout
        ldw     $16,$29,0
        ldw     $31,$29,4
        add     $29,$29,8
        jr      $31
 
bout:
        sub     $29,$29,8
        stw     $31,$29,4
        stw     $16,$29,0
        add     $16,$4,$0
        slr     $4,$16,4
        jal     nout
        add     $4,$16,$0
        jal     nout
        ldw     $16,$29,0
        ldw     $31,$29,4
        add     $29,$29,8
        jr      $31
 
nout:
        sub     $29,$29,4
        stw     $31,$29,0
        and     $4,$4,0x0F
        add     $4,$4,0x30
        sub     $8,$4,0x3A
        blt     $8,$0,nout1
        add     $4,$4,7
nout1:
        jal     cout
        ldw     $31,$29,0
        add     $29,$29,4
        jr      $31
 
cin:
        add     $8,$0,termbase
cin1:
        ldw     $9,$8,0
        and     $9,$9,1
        beq     $9,$0,cin1
        ldw     $2,$8,4
        jr      $31
 
cout:
        add     $8,$0,termbase
cout1:
        ldw     $9,$8,8
        and     $9,$9,1
        beq     $9,$0,cout1
        stw     $4,$8,12
        jr      $31
 
echo:
        sub     $29,$29,4
        stw     $31,$29,0
        jal     cin
        add     $4,$0,$2
        jal     cout
        ldw     $31,$29,0
        add     $29,$29,4
        jr      $31
 
signon:
        .byte   0x0D, 0x0A
        .byte   "ROM Bootstrap Version 1"
        .byte   0x0D, 0x0A, 0x0D, 0x0A, 0
 
prompt:
        .byte   "#"
        .byte   0
 
dnfmsg:
        .byte   "Disk not found!"
        .byte   0x0D, 0x0A, 0
 
dfmsg:
        .byte   "Disk with 0x"
        .byte   0
 
sctmsg:
        .byte   " sectors found, booting..."
        .byte   0x0D, 0x0A, 0
 
demsg:
        .byte   "Disk error!"
        .byte   0x0D, 0x0A, 0
 
nsgmsg:
        .byte   "MBR signature missing!"
        .byte   0x0D, 0x0A, 0

Browse

Tools

Subversion Repositories eco32

[/] [eco32/] [trunk/] [simtest/] [rom/] [romboot.s] - Blame information for rev 213

Line No.	Rev	Author	Line
1	9	hellwig	`;`
2			`; romboot.s -- the ROM bootstrap`
3			`;`
4
5			`.set termbase,0xF0300000 ; terminal base address`
6			`.set diskbase,0xF0400000 ; disk base address`
7			`.set diskbuffer,0xF0480000 ; disk buffer address`
8			`.set virtbase,0xC0000000 ; base of kernel virtual addresses`
9			`.set virtboot,0xC0000000 ; where to start the bootstrap sector`
10			`.set stacktop,0xC0100000 ; where the stack is located`
11
12			`.set PSW,0`
13			`.set TLB_INDEX,1`
14			`.set TLB_ENTRY_HI,2`
15			`.set TLB_ENTRY_LO,3`
16			`.set TLB_ENTRIES,32`
17
18			`.code`
19
20			`reset:`
21			`j start`
22
23			`interrupt:`
24			`j interrupt`
25
26			`miss:`
27			`j miss`
28
29			`start:`
30			`mvts $0,PSW ; disable interrupts and user mode`
31			`mvts $0,TLB_ENTRY_LO ; invalidate all TLB entries`
32			`add $8,$0,virtbase ; by impossible virtual page number`
33			`add $9,$0,$0`
34			`add $10,$0,TLB_ENTRIES`
35			`tlblp:`
36			`mvts $8,TLB_ENTRY_HI`
37			`mvts $9,TLB_INDEX`
38			`tbwi`
39			`add $8,$8,0x1000 ; all entries must be different`
40			`add $9,$9,1`
41			`bne $9,$10,tlblp`
42			`add $29,$0,stacktop ; set stack pointer`
43			`add $4,$0,signon ; show sign-on message`
44			`jal mout`
45			`cmdlp:`
46			`add $4,$0,prompt ; show prompt`
47			`jal mout`
48			`jal echo`
49			`sub $8,$2,0x0D ; '<ret>'?`
50			`beq $8,$0,rcmdlp`
51			`sub $8,$2,'b' ; 'b'?`
52			`beq $8,$0,boot`
53			`add $4,$0,'?' ; unknown command`
54			`jal cout`
55			`rcmdlp:`
56			`jal crlf`
57			`j cmdlp`
58
59			`boot:`
60			`jal crlf`
61			`add $8,$0,diskbase ; check if disk present`
62			`add $9,$0,1000000 ; retry count`
63			`boot1:`
64			`ldw $16,$8,0 ; get status`
65			`and $10,$16,0x20 ; check if disk ready`
66			`bne $10,$0,boot2 ; ready - exit loop`
67			`sub $9,$9,1`
68			`bne $9,$0,boot1 ; try again`
69			`j nodsk ; enough retries - error`
70			`boot2:`
71			`ldw $16,$8,12 ; check if capacity greater than 0`
72			`beq $16,$0,nodsk ; no - report error`
73			`add $4,$0,dfmsg ; say that we found a disk`
74			`jal mout`
75			`add $4,$16,$0 ; and how many sectors it has`
76			`jal wout`
77			`add $4,$0,sctmsg`
78			`jal mout`
79			`add $8,$0,diskbase ; try to load the boot sector`
80			`add $9,$0,1 ; sector count`
81			`stw $9,$8,4`
82			`add $9,$0,0 ; first sector`
83			`stw $9,$8,8`
84			`add $9,$0,1 ; start command`
85			`stw $9,$8,0`
86			`dskwt:`
87			`ldw $9,$8,0`
88			`and $9,$9,0x10 ; done?`
89			`beq $9,$0,dskwt`
90			`ldw $9,$8,0`
91			`and $9,$9,0x08 ; error?`
92			`bne $9,$0,dskerr`
93			`add $8,$0,diskbuffer ; copy sector`
94			`add $9,$0,virtboot`
95			`add $10,$0,512`
96			`dskcp:`
97			`ldw $11,$8,0`
98			`stw $11,$9,0`
99			`add $8,$8,4`
100			`add $9,$9,4`
101			`sub $10,$10,4`
102			`bne $10,$0,dskcp`
103			`add $8,$0,virtboot ; signature present?`
104			`ldbu $9,$8,512-2`
105			`sub $9,$9,0x55`
106			`bne $9,$0,nosig`
107			`ldbu $9,$8,512-1`
108			`sub $9,$9,0xAA`
109			`bne $9,$0,nosig`
110			`jalr $8 ; finally... lift off`
111			`j cmdlp ; in case we ever return to here`
112
113			`nodsk:`
114			`add $4,$0,dnfmsg ; there is no disk`
115			`jal mout`
116			`j cmdlp`
117
118			`dskerr:`
119			`add $4,$0,demsg ; disk error`
120			`jal mout`
121			`j cmdlp`
122
123			`nosig:`
124			`add $4,$0,nsgmsg ; no signature`
125			`jal mout`
126			`j cmdlp`
127
128			`crlf:`
129			`sub $29,$29,4`
130			`stw $31,$29,0`
131			`add $4,$0,0x0D`
132			`jal cout`
133			`add $4,$0,0x0A`
134			`jal cout`
135			`ldw $31,$29,0`
136			`add $29,$29,4`
137			`jr $31`
138
139			`mout:`
140			`sub $29,$29,8`
141			`stw $31,$29,4`
142			`stw $16,$29,0`
143			`add $16,$4,$0`
144			`mout1:`
145			`ldbu $4,$16,0`
146			`beq $4,$0,mout2`
147			`jal cout`
148			`add $16,$16,1`
149			`j mout1`
150			`mout2:`
151			`ldw $16,$29,0`
152			`ldw $31,$29,4`
153			`add $29,$29,8`
154			`jr $31`
155
156			`wout:`
157			`sub $29,$29,8`
158			`stw $31,$29,4`
159			`stw $16,$29,0`
160			`add $16,$4,$0`
161			`slr $4,$16,16`
162			`jal hout`
163			`add $4,$16,$0`
164			`jal hout`
165			`ldw $16,$29,0`
166			`ldw $31,$29,4`
167			`add $29,$29,8`
168			`jr $31`
169
170			`hout:`
171			`sub $29,$29,8`
172			`stw $31,$29,4`
173			`stw $16,$29,0`
174			`add $16,$4,$0`
175			`slr $4,$16,8`
176			`jal bout`
177			`add $4,$16,$0`
178			`jal bout`
179			`ldw $16,$29,0`
180			`ldw $31,$29,4`
181			`add $29,$29,8`
182			`jr $31`
183
184			`bout:`
185			`sub $29,$29,8`
186			`stw $31,$29,4`
187			`stw $16,$29,0`
188			`add $16,$4,$0`
189			`slr $4,$16,4`
190			`jal nout`
191			`add $4,$16,$0`
192			`jal nout`
193			`ldw $16,$29,0`
194			`ldw $31,$29,4`
195			`add $29,$29,8`
196			`jr $31`
197
198			`nout:`
199			`sub $29,$29,4`
200			`stw $31,$29,0`
201			`and $4,$4,0x0F`
202			`add $4,$4,0x30`
203			`sub $8,$4,0x3A`
204			`blt $8,$0,nout1`
205			`add $4,$4,7`
206			`nout1:`
207			`jal cout`
208			`ldw $31,$29,0`
209			`add $29,$29,4`
210			`jr $31`
211
212			`cin:`
213			`add $8,$0,termbase`
214			`cin1:`
215			`ldw $9,$8,0`
216			`and $9,$9,1`
217			`beq $9,$0,cin1`
218			`ldw $2,$8,4`
219			`jr $31`
220
221			`cout:`
222			`add $8,$0,termbase`
223			`cout1:`
224			`ldw $9,$8,8`
225			`and $9,$9,1`
226			`beq $9,$0,cout1`
227			`stw $4,$8,12`
228			`jr $31`
229
230			`echo:`
231			`sub $29,$29,4`
232			`stw $31,$29,0`
233			`jal cin`
234			`add $4,$0,$2`
235			`jal cout`
236			`ldw $31,$29,0`
237			`add $29,$29,4`
238			`jr $31`
239
240			`signon:`
241			`.byte 0x0D, 0x0A`
242			`.byte "ROM Bootstrap Version 1"`
243			`.byte 0x0D, 0x0A, 0x0D, 0x0A, 0`
244
245			`prompt:`
246			`.byte "#"`
247			`.byte 0`
248
249			`dnfmsg:`
250			`.byte "Disk not found!"`
251			`.byte 0x0D, 0x0A, 0`
252
253			`dfmsg:`
254			`.byte "Disk with 0x"`
255			`.byte 0`
256
257			`sctmsg:`
258			`.byte " sectors found, booting..."`
259			`.byte 0x0D, 0x0A, 0`
260
261			`demsg:`
262			`.byte "Disk error!"`
263			`.byte 0x0D, 0x0A, 0`
264
265			`nsgmsg:`
266			`.byte "MBR signature missing!"`
267			`.byte 0x0D, 0x0A, 0`