feat(utils): moved memtest.s to utils.s

src/utils.s

@@ -0,0 +1,60 @@
+; CHIBI PC-09 Prototype #1 Boot ROM -- Memory Testing Routines
+; Copyright (c) 2024-2025 Amber Zeller, Gale Faraday
+; Licensed under MIT
+
+  INCLUDE "hardware.inc"
+  INCLUDE "serial.inc"
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+;;
+;; Memory Testing Routines
+;;
+;; This family of BIOS routines does not return, upon completion the CHIBI must
+;; be reset.
+;;
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+
+  SECTION MEMTEST
+
+  EXPORT ROBIT
+
+; RAM testing routine. Ported to 6809 from 6800, based on source for ROBIT-2 for
+; MIKBUG.
+ROBIT
+  ldx #STACK_TOP+1     ; bottom of testable SRAM, $0200
+AGAIN@                 ; Store 1 in memory
+  lda #1               ; Set [X] to 1
+  sta 0,x
+  cmpa 0,x             ; If failed print out an error indicator
+  bne ERR@
+NEXT@                  ; Loop point for next address
+  asla                 ; Shift A and [X] left
+  asl 0,x
+  cmpa 0,x             ; Compare A and [X]
+  bne ERR@
+  cmpa #$80            ; Only test up to $80
+  bne NEXT@            ; Loop if not $80
+  cmpx #$60FF          ; Compare X to end of RAM
+  beq PASS@            ; Finish if we're at the end
+  leax 1,x             ; Increment X
+  bra AGAIN@
+ERR@                   ; Write out error indicator
+  ldb #'X
+  jsr POUTCHAR
+PASS@                  ; Pass test
+  ldb #'P
+  jsr POUTCHAR
+  bra HALT
+
+; Prints a message about completing a memory test prompting the user to reset
+; then puts the MPU in a loop where it only responds to interrupts, effectively
+; halting the CHIBI
+HALT
+  PZSTR MSG_FINISH
+LOOP@
+  sync
+  bra LOOP@
+
+MSG_FINISH
+  fcc "Memory test finished! Please reset"
+  fcb $0D,$0A,$00