From b8c6eaf4c99e405502348c44468961cbe1a71b1d Mon Sep 17 00:00:00 2001
From: Joppe Blondel <joppe@joppeb.nl>
Date: Fri, 9 Oct 2026 11:50:14 +0200
Subject: [PATCH] Added calibration specific error codes

---
 apps/basic/basic.asm | 11 ++++++++---
 tape.asm             | 45 +++++++++++++++++++++++++++++++-------------
 2 files changed, 40 insertions(+), 16 deletions(-)

diff --git a/apps/basic/basic.asm b/apps/basic/basic.asm
index be96293..8e8a8fe 100644
--- a/apps/basic/basic.asm
+++ b/apps/basic/basic.asm
@@ -4649,7 +4649,7 @@ CLOADB: inc     hl              ; skip #
         ; hl contains block, check block type
         ld      a,(hl)
         cp      1               ; first block needs to be a header
-        jr      nz,CLNOHDR      ; First block is not a header
+        jp      nz,CLNOHDR      ; First block is not a header
         ; first block is a header, get nr of blocks
         inc     hl
         ld      de,(hl)
@@ -4706,7 +4706,9 @@ CLREADBLOCK:
         jr      nc,2$
         ; error, make sure it is silent again
         push    af
+        push    bc              ; save specific error code
         call    BIOS_CAS_WAIT_SILENCE
+        pop     bc     
         pop     af
         jr      CLERR
 1$:     push    hl              ; save hl
@@ -4727,7 +4729,10 @@ CLERR:  cp      1
         cp      4
         jr      z,CLECHS
         jp      FCERR           ; Unknown error
-CLECAL: ld      hl, CLECALMSG
+CLECAL: ld      h,0
+        ld      l,b             ; get specific error code
+        call    PRNTHL          ; print specific error code
+        ld      hl, CLECALMSG
         jr      CLEPRINT
 CLESYN: ld      hl, CLESYNMSG
         jr      CLEPRINT
@@ -4745,7 +4750,7 @@ CLEPRINT:
         jp      FCERR
 
 CLSTARTMSG:     .db "Play tape...",0ah,0dh,00h
-CLECALMSG:      .db "Calibration failed",0ah,0dh,00h
+CLECALMSG:      .db " - Calibration failed",0ah,0dh,00h
 CLESYNMSG:      .db "Synchronization failed",0ah,0dh,00h
 CLEREDMSG:      .db "Read failed",0ah,0dh,00h
 CLECHSMSG:      .db "Checksum error",0ah,0dh,00h
diff --git a/tape.asm b/tape.asm
index b1a06eb..aba9e92 100644
--- a/tape.asm
+++ b/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$