# Hexdisp.asm

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## Latest revision as of 08:36, 4 December 2010

## Contents |

# Functions Provided

Entry point | Function provided | Notes |
---|---|---|

HEX16 | Print a hexadecimal number | Prints a 16-bit hexadecimal number |

HEX12M | Prints the 12 most significant bits as a 3 digit hexadecimal number | |

HEX8M | Prints the 8 most significant bits as a 2 digit hexadecimal number | |

HEX4M | Prints the 4 most significant bits as a 1 digit hexadecimal number | |

HEX12 | Prints the 12 least significant bits as a 3 digit hexadecimal number | |

HEX8 | Prints the 8 least significant bits as a 2 digit hexadecimal number | |

HEX4 | Prints the 4 least significant bits as a 1 digit hexadecimal number |

See source code below for calling convention.

# Examples

(todo... please contribute!)

# Notes

If you only need to print 16-bit hex numbers, you can use hex16.asm instead. hex16.asm and this file cannot coexist in the same program though. These functions are mostly meant for debug and other non-game purposes anyway.

# Source Code

;* ======================================================================== *; ;* These routines are placed into the public domain by their author. All *; ;* copyright rights are hereby relinquished on the routines and data in *; ;* this file. -- Joseph Zbiciak, 2008 *; ;* ======================================================================== *; ;;==========================================================================;; ;; NOTE: IF YOU NEED ONLY HEX16, THAT IS CONTAINED IN A SEPARATE FILE ;; ;; CALLED "hex16.asm". THIS FILE AND THAT ONE CANNOT BE USED TOGETHER. ;; ;;==========================================================================;; ;; ======================================================================== ;; ;; HEX16 -- Display a 4-digit hex number on the screen ;; ;; HEX12M -- Display a 3-digit hex number on the screen (MSBs) ;; ;; HEX8M -- Display a 2-digit hex number on the screen (MSBs) ;; ;; HEX4M -- Display a 1-digit hex number on the screen (MSBs) ;; ;; HEX12 -- Display a 3-digit hex number on the screen (LSBs) ;; ;; HEX8 -- Display a 2-digit hex number on the screen (LSBs) ;; ;; HEX4 -- Display a 1-digit hex number on the screen (LSBs) ;; ;; ;; ;; INPUTS: ;; ;; R0 -- Hex number ;; ;; R1 -- Color mask ;; ;; R4 -- Screen offset ;; ;; ;; ;; OUTPUTS: ;; ;; R0 -- trashed ;; ;; R1 -- unmodified ;; ;; R2 -- trashed ;; ;; R3 -- zeroed ;; ;; R4 -- points just to right of string ;; ;; ======================================================================== ;; HEX16 PROC MVII #4, R3 B @@start HEX12: SLL R0, 2 SLL R0, 2 HEX12M: MVII #3, R3 B @@start HEX8: SWAP R0 HEX8M: MVII #2, R3 B @@start HEX4: SWAP R0 SLL R0, 2 SLL R0, 2 HEX4M: MVII #1, R3 @@start: ; Rotate R0 left by 3, so that our digit will be in the correct ; position within the screen format word. MOVR R0, R2 SLLC R2, 2 RLC R0, 2 ; First, rotate by two bits... SLLC R2, 1 RLC R0, 1 ; ... and then by one more. @@loop: ; Rotate R0 left by 4, so that we can cycle through each digit ; one at a time. MOVR R0, R2 SLLC R2, 2 RLC R0, 2 ; First, rotate by two bits... SLLC R2, 2 RLC R0, 2 ; ... and then by two more. ; Mask out a single hex digit MOVR R0, R2 ANDI #$78, R2 ; Is it A..F? If so, add an offset so that the correct ASCII ; value is selected. Otherwise do nothing special. CMPI #$50, R2 ; $50 is $A shifted left by 3. BLT @@digit ADDI #$38, R2 ; If the digit >= A, add 6 << 3. @@digit: ADDI #$80, R2 ; Generate proper GROM index. XORR R1, R2 ; Merge in the screen format word MVO@ R2, R4 ; Display the digit to the screen. DECR R3 ; Iterate up to three more times. BNE @@loop JR R5 ENDP ;; ======================================================================== ;; ;; End of File: hexdisp.asm ;; ;; ======================================================================== ;;