reading images form file

README.md

@@ -16,3 +16,5 @@ oled
 ```
 
 Now paste your image hex data as generated by `oled-to-hex`.
+
+You can also specify path to `OBM` file to load it from disk.

oled.mac

@@ -7,6 +7,15 @@ LF   EQU  0Ah       ; new line
 BDOS EQU  0005h     ; BDOS entry point
 PSTR EQU  09h       ; print string
 CRED EQU  01h       ; read console
+FOPE EQU  0Fh       ; file open
+FRED EQU  14h       ; file read next record
+
+FCB       EQU  5Ch     ; File Control Block
+FCBFNAME  EQU  FCB+01h ; FCB File Name
+FCBEX     EQU  FCB+0Ch ; FCB Excent Number
+FCBRC     EQU  FCB+0Fh ; FCB Record Count
+FCBCR     EQU  FCB+20h ; FCB Current Record
+FB        EQU  80h     ; File Buffer
 
 OLED EQU  50h  ; base addr of OLED card
 ORST EQU  04h  ; reset command (H)
@@ -22,7 +31,7 @@ OROWD EQU  0B3h  ; select bottom row
 
 OCOL0 EQU  04h  ; left most column
 OSELC EQU  10h  ; select column command
-OCOLL EQU  80h  ; column count: 128 columns
+OCOL  EQU  80h  ; column count: 128 columns
 
 ; 128 columns from 4 to 131
 ; 1Xh, 0Yh - XY = 04h to 83h
@@ -30,28 +39,93 @@ OCOLL EQU  80h  ; column count: 128 columns
 ; MAIN
 CALL OINIT     ; init OLED
 CALL OCLS      ; clear screen
-CALL PROMPT    ; print prompt
-
 CALL OCSTART   ; go to start
-CALL READLINE  ; read row A
-CALL READLINE  ; read row B
-CALL READLINE  ; read row C
-CALL READLINE  ; read row D
 
+LD   A,(FCBFNAME)   ; load first char of file name
+CP   ' '            ; check file name provided
+
+JP   NZ,MAIN1
+CALL PROMPTREAD     ; read from prompt
 RET                 ; exit to CP/M
 
+MAIN1:
+CALL FILEREAD  ; read from file
+RET            ; exit to CP/M
+
+PROMPTREAD:
+     LD   DE,MSGPROMPT
+     CALL PRINT    ; print prompt
+
+     CALL READLINE  ; read row A
+     CALL READLINE  ; read row B
+     CALL READLINE  ; read row C
+     CALL READLINE  ; read row D
+     RET
+
+FILEREAD:
+     LD   DE,MSGFILEREAD
+     CALL PRINT       ; print reading from file
+     XOR  A
+     LD   (FCBEX),A   ; select 0'th extent
+     LD   (FCBRC),A   ; clear
+     LD   (FCBCR),A   ; select 0'th record
+     LD   C,FOPE      ; open file
+     LD   DE,FCB      ; use default FCB
+     CALL BDOS
+     CP   0FFh        ; is error
+     JP   Z,FILEREAD1
+     XOR  A
+     LD   (FCBCR),A   ; start from beginning
+     CALL READRECORD  ; read 128 byte record
+     CALL READRECORD
+     CALL READRECORD
+     CALL READRECORD
+     RET
+FILEREAD1:
+     LD   DE,MSGOPENERR
+     CALL PRINT
+     LD   A,0FFh
+     RET
 
 READLINE:
-     LD   D,OCOLL   ; number of columns
+     LD   D,OCOL        ; number of columns
 READLINE1:
      PUSH DE
      CALL READHEX       ; read hex input from console
      CALL ODATA         ; write to OLED
      POP  DE
-     DEC  D         ; count donw columns
+     DEC  D             ; count down columns
      JP   NZ,READLINE1  ; next column
      RET
 
+; reads block using default FCB
+; A=0 - OK
+; A=FFh - error
+READRECORD:
+     LD   C,FRED    ; read file
+     LD   DE,FCB    ; use default FCB
+     CALL BDOS
+     CP   0         ; check status code
+     JP   NZ,READRECORD1
+     LD   D,OCOL    ; bytes to read
+     LD   HL,FB     ; start of file buffer
+READRECORD0:
+     LD   A,(HL)    ; load byte
+     PUSH DE
+     PUSH HL
+     CALL ODATA     ; send to oled
+     POP  HL
+     POP  DE
+     INC  HL        ; next byte
+     DEC  D         ; count columns down
+     JP   NZ,READRECORD0
+     RET
+READRECORD1:
+     LD   DE,MSGREADERR
+     CALL PRINT
+     LD   A,0FFh    ; error
+     RET
+
 OINIT:
      CALL ORESET      ; reset OLED
      LD   HL,OINITSEQ ; commands to send
@@ -61,7 +135,7 @@ OINITLOOP:
      RET  Z         ; marker reached
      CALL OCOMMAND  ; send command from A
      INC  HL        ; next command
-     JR   OINITLOOP ; send next command 
+     JR   OINITLOOP ; do next command
 
 ORESET:
      LD   C,OLED    ; base I/O address
@@ -98,7 +172,7 @@ OCSTART:
 OCLSROW:
      ;XOR  A        ; display byte to write (0)
      LD   A,0FFh    ; turn on all pixels
-     LD   D,OCOLL   ; count columns in D
+     LD   D,OCOL    ; count columns in D
 OCLSROW1:
      CALL ODATA     ; write A to displey
      DEC  D         ; next column
@@ -139,7 +213,7 @@ ODATA:
 READ:
      LD   C,CRED    ; read from console
      CALL BDOS      ; call CP/M
-     RET            ; A=CHAR
+     RET            ; A=char
 
 ; Reads 4 bit value (0-F)
 READNIB:
@@ -169,15 +243,22 @@ READHEX:
      OR   B         ; OR B to A
      RET
 
-PROMPT:
+; DE - address to $ terminated string
+PRINT:
      LD   C,PSTR    ; load function number
-     LD   DE,PROMPTMSG    ; load string addr
      CALL BDOS      ; call CP/M
      RET
 
-PROMPTMSG: 
+MSGPROMPT:
      DB   'OLED:>', CR, LF,'$' ; string terminated with $
 
+MSGFILEREAD:
+     DB   'Reading from file', CR, LF, '$'
+MSGOPENERR:
+     DB   'Error opening file', CR, LF, '$'
+MSGREADERR:
+     DB   'Error reading file', CR, LF, '$'
+
 ; Initialization sequence
 ; 081h,080h - set contrast (080h full)
 ; 020h,000h - set horizontal window wrapping