Added drom/erom/bank0/bank1 commands to basic

apps/basic/basic.asm

@@ -14,6 +14,7 @@
 ;    - BIOS calls instead of using RST
 ;    - Unsupported functions cause FCERR, not a reset or REM
 ;    - modern backspace handling
+;    - Added DROM/EROM/BANK0/BANK1 commands
 ;
 ;==================================================================================
 ; The updates to the original BASIC within this file are copyright Grant Searle
@@ -45,6 +46,8 @@ MC_BIOS_TRY_GETC        .EQU    BIOS_TRY_GETC
 MC_BIOS_GETC            .EQU    BIOS_GETC
 MC_BIOS_FLUSH           .EQU    BIOS_FLUSH
 MC_BIOS_MONITOR         .EQU    BIOS_RAM_START
+MC_BIOS_ROM             .EQU    BIOS_ROM
+MC_BIOS_BANK            .EQU    BIOS_BANK
 MC_CODE_START           .EQU    BASIC_RAM_START
 MC_RAM_START            .EQU    BASIC_RAM_START + BASIC_ROM_SIZE
 MC_RAM_END              .EQU    0FFFFH
@@ -377,7 +380,10 @@ WORDS:  .BYTE   'E'+80H,"ND"
         .BYTE   'L'+80H,"EFT$"
         .BYTE   'R'+80H,"IGHT$"
         .BYTE   'M'+80H,"ID$"
-        .BYTE   'H'+80H,"ELLO"
+        .BYTE   'D'+80H,"ROM"
+        .BYTE   'E'+80H,"ROM"
+        .BYTE   'B'+80H,"ANK0"
+        .BYTE   'B'+80H,"ANK1"
         .BYTE   80H             ; End of list marker
 
 ; KEYWORD ADDRESS TABLE
@@ -450,7 +456,10 @@ ZLTH    .EQU    0B5H            ; <
 ZSGN    .EQU    0B6H            ; SGN
 ZPOINT  .EQU    0C7H            ; POINT
 ZLEFT   .EQU    0CDH +2         ; LEFT$
-ZHELLO  .EQU    0D2H
+ZDROM   .EQU    0D2H
+ZEROM   .EQU    0D3H
+ZBANK0  .EQU    0D4H
+ZBANK1  .EQU    0D5H
 
 ; ARITHMETIC PRECEDENCE TABLE
 
@@ -1258,12 +1267,30 @@ IFJMP:  RET     Z               ; Go to RUNCNT if end of STMT
 ONJMP:
         ; Own commands
         ; ------------
-CHKHELLO:  
+CHKDROM:  
-        CP      ZHELLO
+        CP      ZDROM
-        JP      NZ,STDONJMP
+        JP      NZ,CHKEROM
-        ld      BC,HELLO
+        ld      BC,DROM
         PUSH    BC
         jp      GETCHR
+CHKEROM:
+        CP      ZEROM
+        JP      NZ,CHKBANK0
+        LD      BC,EROM
+        PUSH    BC
+        JP      GETCHR
+CHKBANK0:
+        CP      ZBANK0
+        JP      NZ,CHKBANK1
+        LD      BC,BANK0
+        PUSH    BC
+        JP      GETCHR
+CHKBANK1:
+        CP      ZBANK1
+        JP      NZ,STDONJMP
+        LD      BC,BANK1
+        PUSH    BC
+        JP      GETCHR
         ; ------------
 STDONJMP:  
         SUB     ZEND            ; Is it a token?
@@ -4379,8 +4406,8 @@ MONOUT: JP      MC_BIOS_PUTC    ; output a char
 
 
 MONITR: CALL    MC_BIOS_FLUSH
-        JP      MC_BIOS_MONITOR ; Restart (Normally Monitor Start)
+        CALL    EROM            ; enable rom
-
+        JP      0               ; reboot
 
 INITST: LD      A,0             ; Clear break flag
         LD      (BRKFLG),A
@@ -4399,14 +4426,29 @@ TSTBIT: PUSH    AF              ; Save bit mask
 OUTNCR: CALL    OUTC            ; Output character in A
         JP      PRNTCRLF        ; Output CRLF
 
-HELLO:
+DROM:                           ; disable ROM
         RET     NZ
-        PUSH    HL
+        LD      A,0
-        LD      HL,HELLOMSG
+        call    MC_BIOS_ROM
-        CALL    PRS
+        RET
-        POP     HL
+
+EROM:                           ; enable ROM
+        RET     NZ
+        LD      A,1
+        call    MC_BIOS_ROM
+        RET
+
+BANK0:                          ; Bank 0
+        RET     NZ
+        LD      A,0
+        call    MC_BIOS_BANK
+        RET
+
+BANK1:                          ; Bank 1
+        RET     NZ
+        LD      A,1
+        call    MC_BIOS_BANK
         RET
-HELLOMSG: .asciz "Hello!"
 
 .end
 

bios.asm

@@ -15,7 +15,7 @@ UART_DATA               .equ UART_BASE+001h
 BUF_SIZE                .equ 16
 BUF_SIZE_MASK           .equ 00fh
 
-WORKSPACE               .equ SHARED_MEM_START+00400h
+WORKSPACE               .equ BIOS_WP_RAM_START
 TX_HEAD                 .equ WORKSPACE+000h
 TX_TAIL                 .equ WORKSPACE+001h
 TX_COUNT                .equ WORKSPACE+002h
@@ -25,6 +25,7 @@ RX_COUNT                .equ WORKSPACE+005h
 TX_BUSY                 .equ WORKSPACE+006h
 TX_BUF                  .equ WORKSPACE+007h
 RX_BUF                  .equ TX_BUF+BUF_SIZE
+SYSREG_VALUE            .equ RX_BUF+BUF_SIZE
 
 ; -------------------------------------------------------
 ; entry
@@ -39,7 +40,7 @@ boot_copy:
     ; banking enabled
     ; bank 1 selected
     ld          a,BOOT_BANK_MAPPING
-    ld          (SYSTEM_REGISTER),a
+    out         (SYSTEM_REGISTER),a
     ld          sp,BIOS_STACK_TOP
     ; copy bios to top 16k
     ld          hl,BIOS_ROM_START
@@ -94,6 +95,10 @@ boot_copy:
     jp          puts
 .org BIOS_FLUSH
     jp          flush
+.ORG BIOS_ROM
+    jp          setrom
+.ORG BIOS_BANK
+    jp          bank
 
 ; -------------------------------------------------------
 ; BIOS ENTRY
@@ -116,6 +121,10 @@ init:
     ld          i,a
     im          2
 
+    ; Set boot bank mapping to sysreg shadow copy
+    ld          a,BOOT_BANK_MAPPING
+    ld          (SYSREG_VALUE),a
+    out         (SYSTEM_REGISTER),a
     ; Initialize tx and rx buffers
     call        buffers_init
     ; Initialize peripherals
@@ -452,6 +461,64 @@ flush:
     ld          a,(TX_COUNT)
     cp          0
     jr          nz,flush
+    ld          a,(TX_BUSY)
+    cp          0
+    jr          nz,flush
+    ret
+
+; -------------------------------------------------------
+; ROM enable/disable
+; needs a (nonzero is enable, zero is disable)
+; -------------------------------------------------------
+setrom:
+    cp          0
+    jr          z,1$
+    ; nonzero -> enable
+    push        bc
+    ld          a,ROM_DISABLE_BIT
+    cpl ; get mask
+    ld          b,a
+    ld          a,(SYSREG_VALUE)
+    and         b
+    ld          (SYSREG_VALUE),a
+    out         (SYSTEM_REGISTER),a
+    pop         bc
+2$:
+    ret
+1$:
+    ; zero -> disable
+    ld          a,(SYSREG_VALUE)
+    or          ROM_DISABLE_BIT
+    ld          (SYSREG_VALUE),a
+    out         (SYSTEM_REGISTER),a
+    jr          2$
+
+; -------------------------------------------------------
+; Select bank
+; needs a (nonzero is bank 1, zero is bank 0)
+; -------------------------------------------------------
+bank:
+    cp          0
+    jr          nz,1$
+    ; zero -> bank 0
+    push        bc
+    ld          a,BANK_SELECT_BIT
+    cpl ; get mask
+    ld          b,a
+    ld          a,(SYSREG_VALUE)
+    and         b
+    ld          (SYSREG_VALUE),a
+    out         (SYSTEM_REGISTER),a
+    pop         bc
+2$:
+    ret
+1$:
+    ; non zero -> bank 1
+    ld          a,(SYSREG_VALUE)
+    or          BANK_SELECT_BIT
+    ld          (SYSREG_VALUE),a
+    out         (SYSTEM_REGISTER),a
+    jr          2$
 
 ; -------------------------------------------------------
 ; Strings

bios.inc

@@ -3,3 +3,5 @@ BIOS_GETC               .equ 0c053h
 BIOS_TRY_GETC           .equ 0c056h
 BIOS_PUTS               .equ 0c059h
 BIOS_FLUSH              .equ 0c05ch
+BIOS_ROM                .equ 0c05fh
+BIOS_BANK               .equ 0c062h

memory.mk

@@ -11,10 +11,11 @@ SHARED_MEM_END          := 0xffff
 
 BIOS_STACK_TOP          := 0xffff
 BIOS_ROM_START          := 0x0080
-BIOS_ROM_SIZE           := 0x0380
+BIOS_ROM_SIZE           := 0x0580
 
-BASIC_ROM_START		:= 0x0400
+BASIC_ROM_START		:= 0x0600
 BASIC_ROM_SIZE		:= 0x2000
 
 BIOS_RAM_START		:= 0xc000
-BASIC_RAM_START		:= 0xc800
+BIOS_WP_RAM_START	:= 0xc600
+BASIC_RAM_START		:= 0xca00