diff options
Diffstat (limited to 'cmpen472hw6_McDonnell/Sources/main.asm')
| -rw-r--r-- | cmpen472hw6_McDonnell/Sources/main.asm | 167 |
1 files changed, 166 insertions, 1 deletions
diff --git a/cmpen472hw6_McDonnell/Sources/main.asm b/cmpen472hw6_McDonnell/Sources/main.asm index 62592ce..1e9eb0c 100644 --- a/cmpen472hw6_McDonnell/Sources/main.asm +++ b/cmpen472hw6_McDonnell/Sources/main.asm @@ -84,6 +84,13 @@ lenBuf dc.w $0010 ; Length of buffer array buffer2 ds.b $0010 ; Array of 16 bytes for reading and reversal dc.b NULL ; NULL terminated lenBuf2 dc.w $0010 ; length of buffer2 + +badAddr dc.b 'invalid input, address',CR,LF,NULL ; Error message for bad address + +badData dc.b 'invalid input, data',CR,LF,NULL ; Error message for bad data + +badCom dc.b 'invalid input, command',CR,LF,NULL ; Error message for bad command + * There is a second Data Section at the end of the file. * ************************************************************************** @@ -134,6 +141,17 @@ mainLoop ldx #Counter jsr PrintMem + ldx #buffer + ldy lenBuf + jsr Zeros + + ldx #buffer + ldy lenBuf + jsr ReadString + + ldx #buffer + jsr ReadDecimal + bra mainLoop ldx #msg ; Load the address of msg into X @@ -179,7 +197,138 @@ twReadLoop jsr getchar ; Read Character from Serial CheckInput rts ; Return to caller + +;************************************************************************* +; ReadHex subroutine +; +; This subroutine will read an ASCII string of a number in hex and convert it to +; its value. +; +; Input: A memory address in register X. +; Output: The value of the hex number in the Y register, and any errors printed +; to the seriel line. Zero bit is set if error occurs. +; Registers in use: X for the address of the contents and for a buffer while printing, +; D for multiplication, B for the character, Y for output value. +; Memory locations in use: Memory Address for serial line, address of the string +; +; Comments: This subroutine will return the value in the Y register, and if an error occurs, +; the Zero bit in the CCR will be set. +; + +ReadHex + pshx ; Save X to the stack + pshd ; Save D to the stack + ldy #0 ; Clear Y register + ldab 1,x+ ; Read character from X into B, add 1 to X + cmpb #'$' ; Compare B to '$' + bne rHError ; If B != '$', jump to error, not hex data +rHLoop ldab 1,x+ ; Read Next character from X + beq rHDone ; If B == 0, exit loop + cmpb #' ' ; Compare B to space character + beq rHDone ; If B == ' ', exit loop + cmpb #'0' ; Compare B to '0' character + blt rHError ; If B < '0', bad address, exit loop + cmpb #'9' ; Compare B to '9' character + bhi rHAlpha ; If B > '9', check if 'A'-'F' characters + subb #'0' ; Subtract '0' from B to get true value + pshb ; Save B to the stack + ldd #16 ; load 16 into D + emul ; Multiply Y and D + exg d,y ; Transfer data from D to Y + pulb ; Restore b from the stack + aby ; Add B to Y + bra rHLoop ; Branch always to rHLoop +rHAlpha cmpb #'A' ; Compare B to 'A' character + blt rHError ; If B < 'A', bad address, exit loop + cmpb #'F' ; Compare B to 'F' character + bhi rHError ; If B > 'F', invalid data, error out + subb #'A' ; Subtract 'A' from B to get true value + addb #$A ; Add $A to B to account for offet + pshb ; Save B to the stack + ldd #16 ; load 16 into D + emul ; Multiply Y and D + exg d,y ; Transfer data from D to Y + pulb ; Restore b from the stack + aby ; Add B to Y + bra rHLoop ; Branch always to rHLoop +rHDone clra ; clear A accumulator + tap ; Transfer A into CCR to clear zero bit + puld ; Restore D from the stack + pulx ; Restore X from the stack + rts ; Return to caller +rHError ldx #badAddr ; Load address of bad address string into X + jsr WriteString ; Write string to seriel output + ldaa #4 ; Load 4 into A to set zero bit in CCR + tap ; Transfer A into CCR to set zero bit and warn error + puld ; Restore D from the stack + pulx ; Restore X from the stack + rts ; Return to caller +;************************************************************************* +; ReadDecimal subroutine +; +; This subroutine will read an ASCII string of a number in decimal and convert it to +; its value. +; +; Input: A memory address in register X. +; Output: The value of the number in the Y register, and any errors printed +; to the seriel line. Zero bit is set if error occurs. +; Registers in use: X for the address of the contents and for a buffer while printing, +; D for multiplication, B for the character, Y for output value. +; Memory locations in use: Memory Address for serial line, address of the string +; +; Comments: This subroutine will return the value in the Y register, and if an error occurs, +; the Zero bit in the CCR will be set. +; + +ReadDecimal + pshx ; Save X to the stack + pshd ; Save D to the stack + ldy #0 ; Clear Y register +dHLoop ldab 1,x+ ; Read Next character from X + beq dHDone ; If B == 0, exit loop + cmpb #' ' ; Compare B to space character + beq dHDone ; If B == ' ', exit loop + cmpb #'0' ; Compare B to '0' character + blt dHError ; If B < '0', bad address, exit loop + cmpb #'9' ; Compare B to '9' character + bhi dHError ; If B > '9', check if 'A'-'F' characters + subb #'0' ; Subtract '0' from B to get true value + pshb ; Save B to the stack + ldd #10 ; load 10 into D + emul ; Multiply Y and D + exg d,y ; Transfer data from D to Y + pulb ; Restore b from the stack + aby ; Add B to Y + bra dHLoop ; Branch always to rHLoop +dHDone clra ; clear A accumulator + tap ; Transfer A into CCR to clear zero bit + puld ; Restore D from the stack + pulx ; Restore X from the stack + rts ; Return to caller +dHError ldx #badAddr ; Load address of bad address string into X + jsr WriteString ; Write string to seriel output + ldaa #4 ; Load 4 into A to set zero bit in CCR + tap ; Transfer A into CCR to set zero bit and warn error + puld ; Restore D from the stack + pulx ; Restore X from the stack + rts ; Return to caller + +;************************************************************************* +; PrintMem subroutine +; +; This subroutine will print the address and contents of the given memory location. +; +; Input: A memory address in register X. +; Output: The memory address in Hex and the contents in binary, hex, & decimal +; on the seriel output. +; Registers in use: X for the address of the contents and for a buffer while printing, +; D for the contents of the location, Y for another buffer address while +; reversing strings and printing. +; Memory locations in use: Memory Address for serial line, address of the string +; +; Comments: This subroutine requires the seriel console to be setup before calling. +; PrintMem pshy ; Save Y to the Stack @@ -221,7 +370,23 @@ PrintMem puld ; Restore D from the stack puly ; Restore Y from the stack rts ; Return to caller - + +;************************************************************************* +; strrev subroutine +; +; This subroutine will reverse a string from one buffer into another. +; +; Input: Address of null terminated string in X, address of a large enough +; buffer in Y. +; Output: The string in X reversed in Y. +; Registers in use: X for the address of the string, Y for the address of the buffer, +; A to read characters from the string. +; Memory locations in use: Memory Address for serial line, address of the string & buffer +; +; Comments: This subroutine will not check that the output buffer is large enough, that +; is the job of the caller. +; + strrev pshx ; Save X to the stack pshy ; Save Y to the stack |