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https://opencores.org/ocsvn/eco32/eco32/trunk
Subversion Repositories eco32
[/] [eco32/] [trunk/] [monitor/] [monitor/] [boards/] [xsa-xst-3/] [start.s] - Rev 104
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; ; start.s -- ECO32 ROM monitor startup and support routines ; .set dmapaddr,0xC0000000 ; base of directly mapped addresses .set stacktop,0xC0010000 ; monitor stack is at top of 64K .set PSW,0 ; reg # of PSW .set V_SHIFT,27 ; interrupt vector ctrl bit .set V,1 << V_SHIFT .set TLB_INDEX,1 ; reg # of TLB Index .set TLB_ENTRY_HI,2 ; reg # of TLB EntryHi .set TLB_ENTRY_LO,3 ; reg # of TLB EntryLo .set TLB_ENTRIES,32 ; number of TLB entries .set BAD_ADDRESS,4 ; reg # of bad address reg .set USER_CONTEXT_SIZE,37*4 ; size of user context ;*************************************************************** .import _ecode .import _edata .import _ebss .import kbdinit .import kbdinchk .import kbdin .import dspinit .import dspoutchk .import dspout .import serinit .import ser0inchk .import ser0in .import ser0outchk .import ser0out .import sctcapctl .import sctioctl .import sctcapser .import sctioser .import main .export _bcode .export _bdata .export _bbss .export cinchk .export cin .export coutchk .export cout .export sinchk .export sin .export soutchk .export sout .export dskcap .export dskio .export setISR .export setUMSR .export isrPtr .export umsrPtr .export getTLB_HI .export getTLB_LO .export setTLB .export saveState .export monitorReturn .import userContext .export resume ;*************************************************************** .code _bcode: .data _bdata: .bss _bbss: ;*************************************************************** .code .align 4 reset: j start interrupt: j isr userMiss: j umsr ;*************************************************************** .code .align 4 cinchk: ; j kbdinchk j ser0inchk cin: ; j kbdin j ser0in coutchk: ; j dspoutchk j ser0outchk cout: ; j dspout j ser0out sinchk: j ser0inchk sin: j ser0in soutchk: j ser0outchk sout: j ser0out dskcap: j dcap dskio: j dio reserved1: j reserved1 reserved2: j reserved2 reserved3: j reserved3 setISR: j setISR1 setUMSR: j setUMSR1 ;*************************************************************** .code .align 4 start: ; let irq/exc vectors point to RAM add $8,$0,V mvts $8,PSW ; initialize TLB mvts $0,TLB_ENTRY_LO ; invalidate all TLB entries add $8,$0,dmapaddr ; by impossible virtual page number add $9,$0,$0 add $10,$0,TLB_ENTRIES tlbloop: 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,tlbloop ; copy data segment add $10,$0,_bdata ; lowest dst addr to be written to add $8,$0,_edata ; one above the top dst addr sub $9,$8,$10 ; $9 = size of data segment add $9,$9,_ecode ; data is waiting right after code j cpytest cpyloop: ldw $11,$9,0 ; src addr in $9 stw $11,$8,0 ; dst addr in $8 cpytest: sub $8,$8,4 ; downward sub $9,$9,4 bgeu $8,$10,cpyloop ; clear bss segment add $8,$0,_bbss ; start with first word of bss add $9,$0,_ebss ; this is one above the top j clrtest clrloop: stw $0,$8,0 ; dst addr in $8 add $8,$8,4 ; upward clrtest: bltu $8,$9,clrloop ; now do some useful work add $29,$0,stacktop ; setup monitor stack jal dspinit ; init display jal kbdinit ; init keyboard jal serinit ; init serial interface jal main ; enter command loop ; main should never return j start ; just to be sure... ;*************************************************************** .code .align 4 ; Word getTLB_HI(int index) getTLB_HI: mvts $4,TLB_INDEX tbri mvfs $2,TLB_ENTRY_HI jr $31 ; Word getTLB_LO(int index) getTLB_LO: mvts $4,TLB_INDEX tbri mvfs $2,TLB_ENTRY_LO jr $31 ; void setTLB(int index, Word entryHi, Word entryLo) setTLB: mvts $4,TLB_INDEX mvts $5,TLB_ENTRY_HI mvts $6,TLB_ENTRY_LO tbwi jr $31 ;*************************************************************** .code .align 4 ; int dskcap(int dskno) dcap: bne $4,$0,dcapser j sctcapctl dcapser: j sctcapser ; int dskio(int dskno, char cmd, int sct, Word addr, int nscts) dio: bne $4,$0,dioser add $4,$5,$0 add $5,$6,$0 add $6,$7,$0 ldw $7,$29,16 j sctioctl dioser: add $4,$5,$0 add $5,$6,$0 add $6,$7,$0 ldw $7,$29,16 j sctioser ;*************************************************************** .code .align 4 ; void setISR(Word ptr) setISR1: stw $4,$0,isrPtr jr $31 ; void setUMSR(Word ptr) setUMSR1: stw $4,$0,umsrPtr jr $31 .data .align 4 isrPtr: .word 0 umsrPtr: .word 0 ;*************************************************************** .code .align 4 ; Bool saveState(MonitorState *msp) ; always return 'true' here saveState: stw $31,$4,0*4 ; return address stw $29,$4,1*4 ; stack pointer stw $16,$4,2*4 ; local variables stw $17,$4,3*4 stw $18,$4,4*4 stw $19,$4,5*4 stw $20,$4,6*4 stw $21,$4,7*4 stw $22,$4,8*4 stw $23,$4,9*4 add $2,$0,1 jr $31 ; load state when re-entering monitor ; this appears as if returning from saveState ; but the return value is 'false' here loadState: ldw $8,$0,monitorReturn beq $8,$0,loadState ; fatal error: monitor state lost ldw $31,$8,0*4 ; return address ldw $29,$8,1*4 ; stack pointer ldw $16,$8,2*4 ; local variables ldw $17,$8,3*4 ldw $18,$8,4*4 ldw $19,$8,5*4 ldw $20,$8,6*4 ldw $21,$8,7*4 ldw $22,$8,8*4 ldw $23,$8,9*4 add $2,$0,0 jr $31 .bss .align 4 ; extern MonitorState *monitorReturn monitorReturn: .space 4 ; extern UserContext userContext userContext: .space USER_CONTEXT_SIZE ;*************************************************************** .code .align 4 ; void resume(void) ; use userContext to load state resume: mvts $0,PSW add $28,$0,userContext .nosyn ldw $8,$28,33*4 ; tlbIndex mvts $8,TLB_INDEX ldw $8,$28,34*4 ; tlbEntryHi mvts $8,TLB_ENTRY_HI ldw $8,$28,35*4 ; tlbEntryLo mvts $8,TLB_ENTRY_LO ldw $8,$28,36*4 ; badAddress mvts $8,BAD_ADDRESS ;ldw $0,$28,0*4 ; registers ldw $1,$28,1*4 ldw $2,$28,2*4 ldw $3,$28,3*4 ldw $4,$28,4*4 ldw $5,$28,5*4 ldw $6,$28,6*4 ldw $7,$28,7*4 ldw $8,$28,8*4 ldw $9,$28,9*4 ldw $10,$28,10*4 ldw $11,$28,11*4 ldw $12,$28,12*4 ldw $13,$28,13*4 ldw $14,$28,14*4 ldw $15,$28,15*4 ldw $16,$28,16*4 ldw $17,$28,17*4 ldw $18,$28,18*4 ldw $19,$28,19*4 ldw $20,$28,20*4 ldw $21,$28,21*4 ldw $22,$28,22*4 ldw $23,$28,23*4 ldw $24,$28,24*4 ldw $25,$28,25*4 ldw $26,$28,26*4 ldw $27,$28,27*4 ;ldw $28,$28,28*4 ldw $29,$28,29*4 ldw $30,$28,30*4 ldw $31,$28,31*4 ldw $28,$28,32*4 ; psw mvts $28,PSW rfx .syn ; interrupt entry ; use userContext to store state isr: umsr: .nosyn ldhi $28,userContext or $28,$28,userContext stw $0,$28,0*4 ; registers stw $1,$28,1*4 stw $2,$28,2*4 stw $3,$28,3*4 stw $4,$28,4*4 stw $5,$28,5*4 stw $6,$28,6*4 stw $7,$28,7*4 stw $8,$28,8*4 stw $9,$28,9*4 stw $10,$28,10*4 stw $11,$28,11*4 stw $12,$28,12*4 stw $13,$28,13*4 stw $14,$28,14*4 stw $15,$28,15*4 stw $16,$28,16*4 stw $17,$28,17*4 stw $18,$28,18*4 stw $19,$28,19*4 stw $20,$28,20*4 stw $21,$28,21*4 stw $22,$28,22*4 stw $23,$28,23*4 stw $24,$28,24*4 stw $25,$28,25*4 stw $26,$28,26*4 stw $27,$28,27*4 stw $28,$28,28*4 stw $29,$28,29*4 stw $30,$28,30*4 stw $31,$28,31*4 mvfs $8,PSW stw $8,$28,32*4 ; psw mvfs $8,TLB_INDEX stw $8,$28,33*4 ; tlbIndex mvfs $8,TLB_ENTRY_HI stw $8,$28,34*4 ; tlbEntryHi mvfs $8,TLB_ENTRY_LO stw $8,$28,35*4 ; tlbEntryLo mvfs $8,BAD_ADDRESS stw $8,$28,36*4 ; badAddress .syn j loadState
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