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https://opencores.org/ocsvn/eco32/eco32/trunk
Subversion Repositories eco32
[/] [eco32/] [trunk/] [monitor/] [monitor/] [boards/] [simulator/] [start.s] - Rev 331
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; ; start.s -- ECO32 ROM monitor startup and support routines ; ; .set CIO_CTL,0x00 ; set console to keyboard/display .set CIO_CTL,0x03 ; set console to serial line 0 .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 BAD_ACCESS,5 ; reg # of bad access reg .set USER_CONTEXT_SIZE,38*4 ; size of user context ;*************************************************************** .import _ecode .import _edata .import _ebss .import kbdinit .import kbdinchk .import kbdin .import dspinit .import dspoutchk .import dspout .import ser0init .import ser0inchk .import ser0in .import ser0outchk .import ser0out .import ser1init .import ser1inchk .import ser1in .import ser1outchk .import ser1out .import dskinitctl .import dskcapctl .import dskioctl .import dskinitser .import dskcapser .import dskioser .import main .export _bcode .export _bdata .export _bbss .export setcon .export cinchk .export cin .export coutchk .export cout .export dskcap .export dskio .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 startup: j start interrupt: j debug userMiss: j debug monitor: j debug ;*************************************************************** .code .align 4 setcon: j setcio cinchk: j cichk cin: j ci coutchk: j cochk cout: j co dskcap: j dcap dskio: j dio reserved_11: j reserved_11 reserved_12: j reserved_12 reserved_13: j reserved_13 reserved_14: j reserved_14 reserved_15: j reserved_15 ;*************************************************************** .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 mvts $8,TLB_ENTRY_HI add $8,$0,$0 add $9,$0,TLB_ENTRIES tlbloop: mvts $8,TLB_INDEX tbwi add $8,$8,1 bne $8,$9,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 ; initialize I/O add $29,$0,stacktop ; setup monitor stack add $4,$0,CIO_CTL ; set console jal setcio ldbu $8,$0,cioctl ; get control byte and $8,$8,0x01 ; keyboard input wanted? bne $8,$0,nokbd ; no - then don't touch jal kbdinit ; else init keyboard nokbd: ldbu $8,$0,cioctl ; get control byte and $8,$8,0x02 ; display output wanted? bne $8,$0,nodsp ; no - then don't touch jal dspinit ; else init display nodsp: jal ser0init ; init serial line 0 jal ser1init ; init serial line 1 jal dskinitctl ; init disk (controller) jal dskinitser ; init disk (serial line) ; call main 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 ;*************************************************************** .data .align 4 cioctl: .byte 0 .code .align 4 ; void setcon(Byte ctl) setcio: stb $4,$0,cioctl j $31 ; int cinchk(void) cichk: ldbu $8,$0,cioctl and $8,$8,0x01 bne $8,$0,cichk1 j kbdinchk cichk1: j ser0inchk ; char cin(void) ci: ldbu $8,$0,cioctl and $8,$8,0x01 bne $8,$0,ci1 j kbdin ci1: j ser0in ; int coutchk(void) cochk: ldbu $8,$0,cioctl and $8,$8,0x02 bne $8,$0,cochk1 j dspoutchk cochk1: j ser0outchk ; void cout(char c) co: ldbu $8,$0,cioctl and $8,$8,0x02 bne $8,$0,co1 j dspout co1: j ser0out ;*************************************************************** .code .align 4 ; int dskcap(int dskno) dcap: bne $4,$0,dcapser j dskcapctl dcapser: j dskcapser ; 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 dskioctl dioser: add $4,$5,$0 add $5,$6,$0 add $6,$7,$0 ldw $7,$29,16 j dskioser ;*************************************************************** .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 $24,$0,userContext .nosyn ldw $8,$24,33*4 ; tlbIndex mvts $8,TLB_INDEX ldw $8,$24,34*4 ; tlbEntryHi mvts $8,TLB_ENTRY_HI ldw $8,$24,35*4 ; tlbEntryLo mvts $8,TLB_ENTRY_LO ldw $8,$24,36*4 ; badAddress mvts $8,BAD_ADDRESS ldw $8,$24,37*4 ; badAccess mvts $8,BAD_ACCESS ;ldw $0,$24,0*4 ; registers ldw $1,$24,1*4 ldw $2,$24,2*4 ldw $3,$24,3*4 ldw $4,$24,4*4 ldw $5,$24,5*4 ldw $6,$24,6*4 ldw $7,$24,7*4 ldw $8,$24,8*4 ldw $9,$24,9*4 ldw $10,$24,10*4 ldw $11,$24,11*4 ldw $12,$24,12*4 ldw $13,$24,13*4 ldw $14,$24,14*4 ldw $15,$24,15*4 ldw $16,$24,16*4 ldw $17,$24,17*4 ldw $18,$24,18*4 ldw $19,$24,19*4 ldw $20,$24,20*4 ldw $21,$24,21*4 ldw $22,$24,22*4 ldw $23,$24,23*4 ;ldw $24,$24,24*4 ldw $25,$24,25*4 ldw $26,$24,26*4 ldw $27,$24,27*4 ldw $28,$24,28*4 ldw $29,$24,29*4 ldw $30,$24,30*4 ldw $31,$24,31*4 ldw $24,$24,32*4 ; psw mvts $24,PSW rfx .syn ; debug entry ; use userContext to store state debug: .nosyn ldhi $24,userContext or $24,$24,userContext stw $0,$24,0*4 ; registers stw $1,$24,1*4 stw $2,$24,2*4 stw $3,$24,3*4 stw $4,$24,4*4 stw $5,$24,5*4 stw $6,$24,6*4 stw $7,$24,7*4 stw $8,$24,8*4 stw $9,$24,9*4 stw $10,$24,10*4 stw $11,$24,11*4 stw $12,$24,12*4 stw $13,$24,13*4 stw $14,$24,14*4 stw $15,$24,15*4 stw $16,$24,16*4 stw $17,$24,17*4 stw $18,$24,18*4 stw $19,$24,19*4 stw $20,$24,20*4 stw $21,$24,21*4 stw $22,$24,22*4 stw $23,$24,23*4 stw $24,$24,24*4 stw $25,$24,25*4 stw $26,$24,26*4 stw $27,$24,27*4 stw $28,$24,28*4 stw $29,$24,29*4 stw $30,$24,30*4 stw $31,$24,31*4 mvfs $8,PSW stw $8,$24,32*4 ; psw mvfs $8,TLB_INDEX stw $8,$24,33*4 ; tlbIndex mvfs $8,TLB_ENTRY_HI stw $8,$24,34*4 ; tlbEntryHi mvfs $8,TLB_ENTRY_LO stw $8,$24,35*4 ; tlbEntryLo mvfs $8,BAD_ADDRESS stw $8,$24,36*4 ; badAddress mvfs $8,BAD_ACCESS stw $8,$24,37*4 ; badAccess .syn j loadState