Subversion Repositories am9080_cpu_based_on_microcoded_am29xx_bit-slices

;--------------------------------------------------------------------------
; Simple test program for Sys9080 project https://github.com/zpekic/sys9080
;               (c) zpekic@hotmail.com - 2017, 2018
;--------------------------------------------------------------------------
ACIA0_STATUS    EQU 0x10; status read-only
ACIA0_DATA      EQU 0x11; data send/receive
ACIA1_STATUS    EQU 0x12; status read-only
ACIA1_DATA      EQU 0x13; data send/receive
PORT_0          EQU 0x00;
PORT_1          EQU 0x01;
MASK_VALID      EQU 0x01; fields in UART status register
MASK_READY      EQU 0x02;
MASK_ERROR      EQU 0x40;
MASK_INTREQ     EQU 0x80;
CR              EQU 0x0D; ASCII newline
LF              EQU 0x0A; ASCII line feed
MASK_BUTTON1    EQU 0x02;
Temp_PC         EQU 0xFF00; can't use DW because the hex file maps to ROM only
AltMon          EQU 0x0400; Altmon is org'd to this location


                ORG 0x0000      ;-----RST0 == RESET
                DI
                JMP Boot

                ORG 0x0008      ;-----RST1 (not used)
                DI
                JMP DumpState

                ORG 0x0010      ;-----RST2 (not used)
                DI
                JMP DumpState

                ORG 0x0018      ;-----RST3 (not used)
                DI
                JMP DumpState

                ORG 0x0020      ;-----RST4 (ACIA1)
                DI
                JMP OnByteReceived

                ORG 0x0028      ;-----RST5 (ACIA0)
                DI
                JMP OnByteReceived

                ORG 0x0030      ;-----RST6 (BTN1)
                EI              ;no interrupt servicing (used to control ACIA status)
                RET

                ORG 0x0038      ;-----RST7 (BTN0)
                DI              
DumpState:      XTHL                    ;PC from stack is now in HL
                SHLD Temp_PC            ;store away (making this code non re-entrant)
                XTHL                    ;restore PC to stack
                PUSH H
                PUSH D
                PUSH B
                PUSH PSW

                PUSH H
                PUSH D
                PUSH B
                PUSH PSW

                LXI H, TextAF
                CALL TxStringAtHL
                XTHL
                CALL TxValueOfHL
                POP H
                
                LXI H, TextBC
                CALL TxStringAtHL
                XTHL
                CALL TxValueOfHL
                CALL BytesAtHL
                POP H

                LXI H, TextDE
                CALL TxStringAtHL
                XTHL
                CALL TxValueOfHL
                CALL BytesAtHL
                POP H

                LXI H, TextHL
                CALL TxStringAtHL
                XTHL
                CALL TxValueOfHL
                CALL BytesAtHL
                POP H

                LXI H, TextPC
                CALL TxStringAtHL
                LHLD Temp_PC
                CALL TxValueOfHL
                CALL BytesAtHL

                LXI H, TextSP
                CALL TxStringAtHL
                LXI D, 0xFFFF           ;start searching for stack position from top of memory down
                LHLD Temp_PC
                XCHG                    ;HL = 0xFFFF, DE = PC to search for
SearchForPC:    MOV A, D
                CMP M
                JNZ NotFound
                DCX H
                MOV A, E
                CMP M
                JNZ SearchForPC
                CALL TxValueOfHL
                CALL BytesAtHL
                MVI A, CR
                CALL SendChar
                JMP RestoreRegs
NotFound:       DCX H
                JMP SearchForPC

RestoreRegs:    POP PSW
                POP B
                POP D
                POP H
                EI
                RET

;-------------------------------------------
OnByteReceived: PUSH PSW
                IN PORT_1               ;hooked up to 4 push buttons
                ANI MASK_BUTTON1
                JZ ProcessByte  
                PUSH H
                PUSH D
                PUSH B

                IN ACIA1_STATUS         
                MOV H, A
                IN ACIA1_DATA
                MOV L, A
                PUSH H

                IN ACIA0_STATUS         
                MOV H, A
                IN ACIA0_DATA
                MOV L, A
                PUSH H

                LXI H, TextACIA0
                CALL TxStringAtHL
                POP H
                CALL TxValueOfHL

                LXI H, TextACIA1
                CALL TxStringAtHL
                POP H
                CALL TxValueOfHL

                POP B
                POP D
                POP H
ProcessByte:    POP PSW
                EI
                RET
;-------------------------------------------
Boot:           LXI H, 0000H
                DCX H
                SPHL
                LXI H, TextGreet1
                CALL TxStringAtHL
                CALL GetLowestRam
                MOV A, L
                OUT PORT_0
                MOV A, H
                OUT PORT_1              ;display on LEDs
                CALL TxValueOfHL        ;display on console
                LXI H, TextPort
                CALL TxStringAtHL
                IN PORT_0
                MOV L, A
                IN PORT_1
                MOV H, A
                CALL TxValueOfHL
                LXI H, TextGreet2
                CALL TxStringAtHL
                CALL PrintAsciiSet
                EI
;               HLT                     ;interrupt is needed to go further
;-------------------------------------------------------------------------
                JMP AltMon              ;enter monitor program
;-------------------------------------------------------------------------
PrintAsciiSet:  LXI B, 0D20H            ;set C to ASCII space
SendNextChar:   MOV A, C
                CALL SendChar           ;send char
                CPI "~"                 ;end of printable chars reached?
                JZ NextLine
                INR C
                JMP SendNextChar
NextLine:       MOV A, B
                CALL SendChar           ;send char
                XRI 00000110B           ;cheap trick to convert newline to linefeed 
                CALL SendChar           ;send char
                RET

TxStringAtHL:   MOV A, M
                ANA A
                RZ
                CALL SendChar
                INX H
                JP TxStringAtHL

BytesAtHL:      MVI C, 0x10             ;dump 16 bytes at (HL)
NextByteAtHL:   MVI A, " "
                CALL SendChar
                MOV A, M
                CALL TxValueOfA
                DCR C
                RZ                      ;return if reached 0
                INX H
                JMP NextByteAtHL

TxValueOfHL:    MOV A, H
                CALL TxValueOfA
                MOV A, L
TxValueOfA:     PUSH PSW
                RRC
                RRC
                RRC
                RRC
                ANI 0x0F
                CALL TxHexDig
                POP PSW
                ANI 0x0F
TxHexDig:       ADI '0'
                CPI '9' + 1
                JM TxHexDigOut
                ADI 0x07
TxHexDigOut:    CALL SendChar
                RET
        
SendChar:       PUSH PSW
CheckIfReady:   IN ACIA0_STATUS
                ANI MASK_READY
                JZ CheckIfReady
                POP PSW
                OUT ACIA0_DATA
                RET
                
GetLowestRam:   LXI H, 0xFFFF   ;assume RAM is located near top of address space
NextAddress:    MOV A, M
                CMP M
                JNZ LowestFound
                CMA             ;flip all bits
                MOV M, A
                CMP M
                JNZ LowestFound
                CMA
                MOV M, A
                MOV A, H
                ORA L
                RZ              ;Bail if HL = 0
                DCX H
                JMP NextAddress
LowestFound:    INX H
                RET
                
                
TextAF:         DB CR, "AF = ", 0x00
TextBC:         DB CR, "BC = ", 0x00
TextDE:         DB CR, "DE = ", 0x00
TextHL:         DB CR, "HL = ", 0x00
TextPC:         DB CR, "PC = ", 0x00
TextSP:         DB CR, "SP = ", 0x00
TextGreet1:     DB CR, CR, "** Sys9080 is ready. RAM starts at ", 0x00
TextPort        DB " Input port = ", 0x00
TextGreet2:     DB " **", CR, "  (Press BTN0 to show processor state, or BTN1 for ACIAs)", CR, 0x00 
TextACIA0:      DB CR, "ACIA0 Rx status and data = ", 0x00
TextACIA1:      DB CR, "ACIA1 Rx status and data = ", 0x00
End:            DB 0x00         ;Cheap trick to see last used address