added PRIMM implementation for easier debugging

CREDITS.md

@@ -9,6 +9,7 @@
 * enthusi/Onslaught - for his example Turbo Tape 64 compatible loader
 * djmips - for fast 8x8 multiplication routine
 * Verz - for the integer division routine
+* Mike Barry - for his PRIMM implementation
 
 ## for documentation
 

STATUS.md

@@ -397,3 +397,16 @@ Not all of them - only these we want to have implemented.
 | `$FF80`   | revision byte                | DONE     |                                                    |
 
 <br />
+
+### API extensions - MEGA65 build
+
+Not all of them - only these we want to have implemented. Note: this is likely to change in the future!
+
+<br />
+
+| Address   | Name     | Status   |  Remarks                                                               |
+| :-------: | :------- | :------: | :--------------------------------------------------------------------: |
+| `$FF7D`   | PRIMM    | DONE     | print immediate, address compatible with C128 and C65 ROMs             |
+| `$FFF8`   |          | DONE     | reset vector for usage within hypervisor, starts in legacy mode        |
+
+<br />

src/aliases/,aliases_ram_lowmem.s

@@ -100,8 +100,8 @@
     !addr COLSTORE  = $9C  ;          [!] screen border storage for tape routines 
 }
 	!addr MSGFLG    = $9D  ;          bit 6 = error messages, bit 7 = control message
-	!addr PTR1      = $9E  ;          for tape support, counter of errorneous bytes
-	!addr PTR2      = $9F  ;          for tape support, counter for errorneous bytes correction
+	!addr PTR1      = $9E  ;          for tape support, counter of errorneous bytes             [!] also used by PRIMM
+	!addr PTR2      = $9F  ;          for tape support, counter for errorneous bytes correction [!] also used by PRIMM
 	!addr TIME      = $A0  ; $A0-$A2  jiffy clock
 	!addr IECPROTO  = $A3  ;          [!] IEC or pseudo-IEC protocol, >= $80 for unknown; originally named TSFCNT
 	!addr TBTCNT    = $A4  ;          temporary variable for tape and IEC, [!] our usage probably differs in details

src/basic/,imports.s

@@ -18,6 +18,7 @@
 ;; #ALIAS# clear_screen        = KERNAL_0.clear_screen
 
 ;; #ALIAS# printf              = KERNAL_0.printf
+;; #ALIAS# PRIMM               = KERNAL_0.PRIMM
 
 ;; #ALIAS# plot_set            = KERNAL_0.plot_set
 ;; #ALIAS# print_hex_byte      = KERNAL_0.print_hex_byte

src/kernal/jumptable_m65/ff7d.jprimm.s

@@ -0,0 +1,11 @@
+;; #LAYOUT# M65 KERNAL_0 #TAKE
+;; #LAYOUT# *   *        #IGNORE
+
+
+; 'Print immediate' - useful debug routine, present on many CBM machines
+; see https://www.pagetable.com/?p=926
+
+
+JPRIMM:
+
+	jmp PRIMM

src/kernal/print/primm.s

@@ -0,0 +1,31 @@
+;; #LAYOUT# M65 KERNAL_0 #TAKE
+;; #LAYOUT# *   *        #IGNORE
+
+
+; 'Print immediate', original implementation by Mike Barry, adapted to 65CE02
+; see http://www.6502.org/source/io/primm.htm
+
+
+PRIMM:
+
+	pla            ; get low part of (string address-1)
+	sta PTR1
+	pla            ; get high part of (string address-1)
+	sta PTR2
+	+bra @2
+@1:
+	jsr JCHROUT    ; output a string char
+@2:
+	inc PTR1       ; advance the string pointer
+	bne @3
+    inc PTR2
+@3:
+	ldy #$00
+	lda (PTR1), y  ; get string char
+	bne @1         ; output and continue if not NUL
+	lda PTR2
+	pha
+	lda PTR1
+	pha
+
+	rts