Added calibration specific error codes

tape.asm

@@ -13,6 +13,18 @@ LONG_MIN                    .equ TAPE_WORKSPACE + 004h ; byte
 LONG_MAX                    .equ TAPE_WORKSPACE + 005h ; byte
 BLOCK_BUFFER                .equ TAPE_WORKSPACE + 006h ; BLOCK_SIZE
 
+; -------------------------------------------------------
+; Error return callback macro
+; creates a simple macro which puts a return code in a
+; and sets the carry flag
+; -------------------------------------------------------
+create_error_return MACRO &name, &code
+&name:
+    ld          a,&code
+    scf
+    ret
+    ENDM
+
 ; -------------------------------------------------------
 ; Measure edge-to-edge pulse
 ; needs d (comparator state)
@@ -133,7 +145,7 @@ make_window:
 ; Calibration
 ; d needs to be kept from now  on
 ; uses a,b,c,e,h,l
-; carry is error
+; carry is error, a contains error code
 ; -------------------------------------------------------
 calibrate:
     ld          a,(TAPE_PORT)   ; get current state
@@ -155,7 +167,7 @@ calibrate:
     ; edge found
     ; get short leader timing
     call        average8
-    jr          c,cal_err       ; timeout
+    jr          c,cal_err_short_leader_average
     ld          (SHORT_AVG),a
     call        make_window
     ld          a,b
@@ -175,9 +187,9 @@ calibrate:
                                 ; is ignored
 4$:
     call        sample_pulse
-    jr          c,cal_err
+    jr          c,cal_err_wait_for_long
     call        sample_pulse
-    jr          c,cal_err
+    jr          c,cal_err_wait_for_long
     ld          a,b
     ; try again if its a short pulse
     cp          c
@@ -187,7 +199,7 @@ calibrate:
     jr          nz,4$           ; repeat this 4 times
     ; long leader found
     call        average8
-    jr          c,cal_err       ; timeout
+    jr          c,cal_err_long_leader_average
     ld          (LONG_AVG),a
     call        make_window
     ld          a,b
@@ -202,7 +214,7 @@ calibrate:
     ld          c,a             ; c = 1.5*short
     ld          a,(LONG_AVG)
     cp          c
-    jr          c,cal_err
+    jr          c,cal_err_sanity_check
     ; Find the marker. marker is 2*long
     ; threshold is 1.5*long
     ld          a,(LONG_AVG)
@@ -215,7 +227,7 @@ calibrate:
     ld          e,0
 6$:
     call        measure_pulse
-    jr          c,cal_err      ; timeout
+    jr          c,cal_err_marker_measure
     ld          a,b
     cp          c
     jr          c,5$            ; not a marker
@@ -227,15 +239,21 @@ calibrate:
     ; we are at the beginning of the first data pulse
     ; next 8 bytes is the training byte 0x55
     call        read_byte
-    jr          c,cal_err
+    jr          c,cal_err_training_read
     cp          a,055h
-    jr          nz,cal_err      ; training byte not 0x55
+    jr          nz,cal_err_training_incorrect
     ; calibration complete
     or          a               ; clear carry
     ret
-cal_err:
-    scf
-    ret
+
+    create_error_return cal_err, 000h
+    create_error_return cal_err_short_leader_average, 001h
+    create_error_return cal_err_wait_for_long, 002h
+    create_error_return cal_err_long_leader_average, 003h
+    create_error_return cal_err_sanity_check, 004h
+    create_error_return cal_err_marker_measure, 005h
+    create_error_return cal_err_training_read, 006h
+    create_error_return cal_err_training_incorrect, 007h
 
 ; -------------------------------------------------------
 ; Read a single bit
@@ -351,7 +369,7 @@ read_sync:
 ; Read a block into BLOCK_BUFFER
 ; needs d (comparator state)
 ; uses b,c,d,e,h,l
-; returns error code in a
+; returns error code in a, specific error code in b
 ; returns start of block in hl
 ; carry is fail
 ; -------------------------------------------------------
@@ -364,6 +382,7 @@ read_block:
     ; calibrate reader
     call        calibrate
     jr          nc,1$           ; if no error jump
+    ld          b,a
     ld          a,BLOCK_ERROR_CALIBRATION
     scf
     jr          101$