more work on Z80 bringup

src/mon_m65/bsmon.s

@@ -38,6 +38,7 @@ Mon_Start:
 ; ********
 
          CLD
+         CLI
          TSY
          STY  SPH
          TSX

src/zvm_m65/debug.s

@@ -24,8 +24,7 @@ DBG_print_PC_opcode:
 	!pet " opcode: ", 0
 
 	pla
-@1:
+	+beq MONITOR
-	beq @1
 	jsr DBGINT_print_hex_byte
 
 	; FALLTROUGH
@@ -57,6 +56,22 @@ DBG_print_hex:
 	bra DBGINT_end
 
 
+DBG_print_LOADCOUNT:
+
+	php
+	pha
+	phx
+	phy
+	phz
+
+	lda BIOS_LOADCOUNT+1
+	jsr DBGINT_print_hex_byte
+	lda BIOS_LOADCOUNT+0
+	jsr DBGINT_print_hex_byte
+	lda #$0D
+	jsr CHROUT
+
+	bra DBGINT_end
 
 
 DBGINT_print_hex_byte:

src/zvm_m65/z80_instr_jump.s

@@ -7,8 +7,10 @@
 Z80_instr_C3:      ; JP nn
 
 	+Z80_FETCH_VIA_PC_INC
+	jsr DBG_print_hex
 	sta REG_PC+0
 	+Z80_FETCH_VIA_PC_INC
+	jsr DBG_print_hex
 	sta REG_PC+1
 	jmp ZVM_next
 

src/zvm_m65/zvm.s

@@ -14,10 +14,11 @@ ZVM: ; entry point
 	; Skip the IRQ processing, even if Kernal reenables it
 
 	sei
-	lda #<return_from_interrupt
+	; XXX uncomment this when debugging is finished
-	sta CINV+0 
+	; lda #<return_from_interrupt
-	lda #>return_from_interrupt
+	; sta CINV+0 
-	sta CINV+1
+	; lda #>return_from_interrupt
+	; sta CINV+1
 
 	; Make sure $C000-$CFFF ROM is mapped-in, we keep our proxies there
 	; Also make sure the palette is taken from RAM

src/zvm_m65/zvm_cputest.s

@@ -111,10 +111,12 @@ ZVM_cputest:
 
 	; Copy up to 512 bytes from buffer to target memory
 
+	inw BIOS_LOADCOUNT
+
 @loop3:
 
 	dew BIOS_LOADCOUNT
-	bmi @loop2
+	beq @loop2 ; XXX why no BMI, without INW?
 
 	lda [BIOS_IOBUFERPTR],z
 	sta [BIOS_LOADPTR],z

src/zvm_m65/zvm_imports.s

@@ -8,9 +8,11 @@
 
 ;; #ALIAS# CHROUT                          = KERNAL_C.proxy_Z1_CHROUT
 
+;; #ALIAS# MONITOR                         = KERNAL_0.MONITOR
 ;; #ALIAS# return_from_interrupt           = KERNAL_0.return_from_interrupt
 
 
+
 ; 'Print immediate', original implementation by Mike Barry, adapted to 65CE02, modified to preserve .Y
 ; see http://www.6502.org/source/io/primm.htm