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| Public notebooks: /services/public/dblank / CS240 Computer Organization / 2015-Fall / Notes | |||
Screen Routines¶
Subroutines to make an 78 x 25 character screen.
- R7 is return value
- R6 is top of stack
- Subroutine (callee) handles saving/loading of return values and registers
In [27]:
.ORIG x4000
;; ------------------------------------------------
;; Graphics Routines
;; 78 x 25 (25th for special status)
;; ------------------------------------------------
;; SETUP
;; RESERVED: R6 for stack
;; R7 for RET value
;; ------------------------------------------------
LEA R6, STACK ;; R6 is Top of STACK
;; ------------------------------------------------
LEA R0, START ;; GOTO START
JMP R0 ;; Keep STACK close to reference
STACK: .BLKW #100 ;; adjust size for your use
START: JSR DRAWSCREEN ;; start of actual program
HALT
;; ------------------------------------------------
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Start of Subroutinues:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; DRAWSCREEN - draw a 80 x 25 screen
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DRAWSCREEN: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;;JSR SAVE_REGS
;;; ---
LD R1, OUTPUT1 ;; read OUTPUTS
LD R2, OUTPUT2 ;; read OUTPUTC
STR R1, R2, #0 ;; save R1 to R2
JSR BORDER ;; draw top border
AND R2, R2, #0 ;; row count is in R2
ROW: JSR SCREENROW
ADD R2, R2, #+1
LD R3, NEGTWENTYFIVE ;; -25
ADD R3, R2, R3
BRn ROW
JSR BORDER
AND R0, R0, #0 ;; terminating \0
JSR OUTPUT
LD R0, OUTPUT1 ;; read OUTPUTS
;;PUTS
;;; ---
;;JSR RESTORE_REGS
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
OUTPUT1: .FILL OUTPUTS ;; store OUTPUTS close
OUTPUT2: .FILL OUTPUTC ;; store OUTPUTC close
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; SCREENROW - draws memory row part of screen
;; - assumes R2 has row count (25, 0)
;; - uses R0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SCREENROW: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;; stuff here
LD R0, BAR
JSR OUTPUT
;; screen row memory is in R2 (initially zero)
;; multiply row x 78 to get next
LD R3, SWIDTH
JSR MULTIPLY ;; R2 x R3 -> R4
;; R4 is now where to start in SCREEN
;; start in SCREEN + R4
;; show each word, for SWIDTH times
ADD R5, R3, #0 ;; copy for countdown
LEA R3, SCREEN ;; start of memory
ADD R3, R3, R4 ;; R3 (screen) + R4 (mult)
LD R1, THIRTYTWO ;; ASCII space; maps 0 to ...
SRAGAIN: LDR R0, R3, #0
ADD R0, R0, R1
JSR OUTPUT
ADD R3, R3, #1
ADD R5, R5, #-1
BRp SRAGAIN
LD R0, BAR
JSR OUTPUT
LD R0, NEWLINE
JSR OUTPUT
;; end here
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
THIRTYTWO: .FILL #32
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; BORDER - draw top/bottom border
;; - uses R0, R1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
BORDER: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
LD R0, PLUS
JSR OUTPUT
AND R1, R1, #0 ;; counter
LD R1, SWIDTH
LD R0, DASH
SAGAIN: JSR OUTPUT
ADD R1, R1, #-1
BRp SAGAIN
LD R0, PLUS
JSR OUTPUT
LD R0, NEWLINE
JSR OUTPUT
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; MULTIPLY - multiplies R2 x R3 -> R4
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
MULTIPLY: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;; ---
AND R4, R4, #0 ;; total
AND R5, R5, #0 ;; counter
ADD R5, R5, R2 ;; set condition codes; R5 is copy of R2
MAGAIN: BRz DONE ;; if R5 == 0, done
ADD R4, R4, R3 ;;
ADD R5, R5, #-1 ;; set condition codes
BR MAGAIN
;; --- result is in R4
DONE: ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; OUTPUT - copy R0 to OUTPUTC (current output)
;; - assumes char in R0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
OUTPUT: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;;JSR SAVE_REGS
;; ---
;;LDI R4, OUTPUT3 ;; Load OUTPUTC (next char pos)
;;STR R0, R4, #0 ;; save R0 char to R1 address
;;ADD R4, R4, #1 ;; increment R1
;;STI R4, OUTPUT3 ;; Save OUTPUTC
OUT
;; ---
;;JSR RESTORE_REGS
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
OUTPUT3: .FILL OUTPUTC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; DATA:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SWIDTH .FILL #78 ;; width of screen
PLUS: .FILL #43 ;; + in ASCII
DASH: .FILL #45 ;; - in ASCII
BAR: .FILL #124 ;; | in ASCII
NEWLINE: .FILL #10 ;; NEWLINE in ASCII
NEGTWENTYFIVE: .FILL #-25
SCREEN: .BLKW #1950 ;; 78 x 25
OUTPUTC: .FILL #0
OUTPUTS: .BLKW #1975 ;; 79 x 25
.END
Screen Display¶
This uses a zero-based display screen where 0 is interpreted to be 0 + 32 = x20 (space in ASCII). See ASCII chart for more characters (0 through 94 are mapped to ASCII 32 through 126). Why? Because no need to attempt to display ASCII 0 through 31, which are control codes).
In [30]:
%mem x40EA x11
In [31]:
%mem x40EB x12
In [32]:
%mem x4138 x13
In [33]:
%%time
%exe
In [34]:
%reset
In [35]:
.ORIG x4000
.SET MODE TERMINAL
;; ------------------------------------------------
;; Graphics Routines
;; 78 x 25 (25th for special status)
;; ------------------------------------------------
;; SETUP
;; RESERVED: R6 for stack
;; R7 for RET value
;; ------------------------------------------------
LEA R6, STACK ;; R6 is Top of STACK
;; ------------------------------------------------
LEA R0, START ;; GOTO START
JMP R0 ;; Keep STACK close to reference
STACK: .BLKW #100 ;; adjust size for your use
START: JSR DRAWSCREEN ;; start of actual program
HALT
;; ------------------------------------------------
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Start of Subroutinues:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; DRAWSCREEN - draw a 80 x 25 screen
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
DRAWSCREEN: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;;JSR SAVE_REGS
;;; ---
LD R1, OUTPUT1 ;; read OUTPUTS
LD R2, OUTPUT2 ;; read OUTPUTC
STR R1, R2, #0 ;; save R1 to R2
JSR BORDER ;; draw top border
AND R2, R2, #0 ;; row count is in R2
ROW: JSR SCREENROW
ADD R2, R2, #+1
LD R3, NEGTWENTYFIVE ;; -25
ADD R3, R2, R3
BRn ROW
JSR BORDER
AND R0, R0, #0 ;; terminating \0
JSR OUTPUT
LD R0, OUTPUT1 ;; read OUTPUTS
;;PUTS
TERMINAL R0, 0
TERMINAL R0, 1
;;; ---
;;JSR RESTORE_REGS
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
OUTPUT1: .FILL OUTPUTS ;; store OUTPUTS close
OUTPUT2: .FILL OUTPUTC ;; store OUTPUTC close
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; SCREENROW - draws memory row part of screen
;; - assumes R2 has row count (25, 0)
;; - uses R0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SCREENROW: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;; stuff here
LD R0, BAR
JSR OUTPUT
;; screen row memory is in R2 (initially zero)
;; multiply row x 78 to get next
LD R3, SWIDTH
JSR MULTIPLY ;; R2 x R3 -> R4
;; R4 is now where to start in SCREEN
;; start in SCREEN + R4
;; show each word, for SWIDTH times
ADD R5, R3, #0 ;; copy for countdown
LEA R3, SCREEN ;; start of memory
ADD R3, R3, R4 ;; R3 (screen) + R4 (mult)
LD R1, THIRTYTWO ;; ASCII space; maps 0 to ...
SRAGAIN: LDR R0, R3, #0
ADD R0, R0, R1
JSR OUTPUT
ADD R3, R3, #1
ADD R5, R5, #-1
BRp SRAGAIN
LD R0, BAR
JSR OUTPUT
LD R0, NEWLINE
JSR OUTPUT
;; end here
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
THIRTYTWO: .FILL #32
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; BORDER - draw top/bottom border
;; - uses R0, R1
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
BORDER: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
LD R0, PLUS
JSR OUTPUT
AND R1, R1, #0 ;; counter
LD R1, SWIDTH
LD R0, DASH
SAGAIN: JSR OUTPUT
ADD R1, R1, #-1
BRp SAGAIN
LD R0, PLUS
JSR OUTPUT
LD R0, NEWLINE
JSR OUTPUT
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; MULTIPLY - multiplies R2 x R3 -> R4
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
MULTIPLY: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;; ---
AND R4, R4, #0 ;; total
AND R5, R5, #0 ;; counter
ADD R5, R5, R2 ;; set condition codes; R5 is copy of R2
MAGAIN: BRz DONE ;; if R5 == 0, done
ADD R4, R4, R3 ;;
ADD R5, R5, #-1 ;; set condition codes
BR MAGAIN
;; --- result is in R4
DONE: ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; OUTPUT - copy R0 to OUTPUTC (current output)
;; - assumes char in R0
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
OUTPUT: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;; ---
LDI R4, OUTPUT3 ;; Load OUTPUTC (next char pos)
STR R0, R4, #0 ;; save R0 char to R1 address
ADD R4, R4, #1 ;; increment R1
STI R4, OUTPUT3 ;; Save OUTPUTC
;;OUT
;; ---
ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
OUTPUT3: .FILL OUTPUTC
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; DATA:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
SWIDTH .FILL #78 ;; width of screen
PLUS: .FILL #43 ;; + in ASCII
DASH: .FILL #45 ;; - in ASCII
BAR: .FILL #124 ;; | in ASCII
NEWLINE: .FILL #10 ;; NEWLINE in ASCII
NEGTWENTYFIVE: .FILL #-25
SCREEN: .BLKW #1950 ;; 78 x 25
OUTPUTC: .FILL #0
OUTPUTS: .BLKW #1975 ;; 79 x 25
.END
In [36]:
%%time
%exe
In [9]:
%%time
%exe
In [10]:
.ORIG x5000
;; ------------------------------------------------
LEA R6, STACK ;; R6 is Top of STACK
;; ------------------------------------------------
LEA R0, START ;; GOTO START
JMP R0 ;; Keep STACK close to reference
STACK: .BLKW #100 ;; adjust size for your use
START: LD R2, FIVE
LD R3, SIX
JSR MULTIPLY
HALT
FIVE: .FILL #5
SIX: .FILL #6
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; MULTIPLY - multiplies R2 x R3 -> R4
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
MULTIPLY: STR R7, R6, #0 ;; Save R7 to Stack
ADD R6, R6, #1 ;; Increment Stack
;;JSR SAVE_REGS
;; ---
AND R4, R4, #0 ;; total
AND R5, R5, #0 ;; counter
ADD R5, R5, R2 ;; set condition codes; R5 is copy of R2
MAGAIN: BRz DONE ;; if R5 == 0, done
ADD R4, R4, R3 ;;
ADD R5, R5, #-1 ;; set condition codes
BR MAGAIN
;; --- result is in R4
;;JSR RESTORE_REGS
DONE: ADD R6, R6, #-1 ;; Decrement Stack
LDR R7, R6, #0 ;; Load Stack into R7
RET
.END
In [11]:
%exe
In [12]:
%reset