From 463c4bddc339272449893b73762765cadeddd98b Mon Sep 17 00:00:00 2001
From: Joppe Blondel <joppe@joppeb.nl>
Date: Wed, 7 Oct 2026 18:00:25 +0200
Subject: [PATCH] added full mode to basic

---
 apps/basic/basic.asm | 98 ++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 95 insertions(+), 3 deletions(-)

diff --git a/apps/basic/basic.asm b/apps/basic/basic.asm
index 142cf1b..96926dc 100644
--- a/apps/basic/basic.asm
+++ b/apps/basic/basic.asm
@@ -384,6 +384,7 @@ WORDS:  .BYTE   'E'+80H,"ND"
         .BYTE   'E'+80H,"ROM"
         .BYTE   'B'+80H,"ANK0"
         .BYTE   'B'+80H,"ANK1"
+        .BYTE   'F'+80H,"ULL"
         .BYTE   80H             ; End of list marker
 
 ; KEYWORD ADDRESS TABLE
@@ -460,6 +461,7 @@ ZDROM   .EQU    0D2H
 ZEROM   .EQU    0D3H
 ZBANK0  .EQU    0D4H
 ZBANK1  .EQU    0D5H
+ZFULL   .EQU    0D6H
 
 ; ARITHMETIC PRECEDENCE TABLE
 
@@ -1287,10 +1289,16 @@ CHKBANK0:
         JP      GETCHR
 CHKBANK1:
         CP      ZBANK1
-        JP      NZ,STDONJMP
+        JP      NZ,CHKFULL
         LD      BC,BANK1
         PUSH    BC
         JP      GETCHR
+CHKFULL:
+        CP      ZFULL
+        JP      NZ,STDONJMP
+        LD      BC,FULL
+        PUSH    BC
+        JP      GETCHR
         ; ------------
 STDONJMP:  
         SUB     ZEND            ; Is it a token?
@@ -1584,6 +1592,9 @@ LET:    CALL    GETVAR          ; Get variable name
 LETSTR: PUSH    HL              ; Save address of string var
         LD      HL,(FPREG)      ; Pointer to string entry
         PUSH    HL              ; Save it on stack
+        LD      A,(BASTXT+1)    ; Full mode has program RAM below BIOS
+        CP      0C0H
+        JP      C,CRESTR        ; Copy strings into the full-mode heap
         INC     HL              ; Skip over length
         INC     HL
         LD      E,(HL)          ; LSB of string address
@@ -4406,7 +4417,8 @@ MONOUT: JP      MC_BIOS_PUTC    ; output a char
 
 
 MONITR: CALL    MC_BIOS_FLUSH
-        CALL    EROM            ; enable rom
+        LD      A,1             ; enable rom
+        call    MC_BIOS_ROM
         JP      0               ; reboot
 
 INITST: LD      A,0             ; Clear break flag
@@ -4428,27 +4440,107 @@ OUTNCR: CALL    OUTC            ; Output character in A
 
 DROM:                           ; disable ROM
         RET     NZ
+        LD      A,(BASTXT+1)    ; Full mode has program RAM below BIOS
+        CP      0C0H
+        JP      C,FCERR         ; Return error in full mode
         LD      A,0
         call    MC_BIOS_ROM
         RET
 
 EROM:                           ; enable ROM
         RET     NZ
+        LD      A,(BASTXT+1)    ; Full mode has program RAM below BIOS
+        CP      0C0H
+        JP      C,FCERR         ; Return error in full mode
         LD      A,1
         call    MC_BIOS_ROM
         RET
 
 BANK0:                          ; Bank 0
         RET     NZ
+        LD      A,(BASTXT+1)    ; Full mode has program RAM below BIOS
+        CP      0C0H
+        JP      C,FCERR         ; Return error in full mode
         LD      A,0
         call    MC_BIOS_BANK
         RET
 
 BANK1:                          ; Bank 1
         RET     NZ
+        LD      A,(BASTXT+1)    ; Full mode has program RAM below BIOS
+        CP      0C0H
+        JP      C,FCERR         ; Return error in full mode
         LD      A,1
         call    MC_BIOS_BANK
         RET
 
-.end
+FULL:                           ; New entry. exposes full 48k ram to basic
+        RET     NZ
 
+        ; FULL BOOT SEQUENCE
+        ; ------------------
+        LD      A,0
+        CALL    MC_BIOS_ROM     ; Expose RAM below the ROM
+
+        LD      HL,WRKSPC       ; Start of workspace RAM
+        LD      SP,HL           ; Set up a temporary stack
+
+        LD      DE,INITAB       ; Initialise workspace
+        LD      B,INITBE-INITAB+3
+        LD      HL,WRKSPC
+FULLCPY:
+        LD      A,(DE)
+        LD      (HL),A
+        INC     HL
+        INC     DE
+        DEC     B
+        JP      NZ,FULLCPY
+
+        LD      SP,HL           ; Temporary stack
+        CALL    CLREG           ; Clear registers and stack
+        CALL    PRNTCRLF
+        XOR     A
+        LD      (BUFFER+72+1),A ; Mark end of input buffer
+
+        LD      HL,0100H        ; Program and variables start here
+        LD      (BASTXT),HL
+
+        LD      HL,FULLMSG      ; Announce the alternate layout
+        CALL    PRS
+
+        LD      HL,SHARED_MEM_START-1
+        JP      FULLSETTOP      ; Finish full-memory initialisation
+
+FULLSETTOP:
+        LD      DE,0-512        ; Reserve 512 bytes for strings
+        LD      (LSTRAM),HL     ; Save last available RAM
+        ADD     HL,DE
+        LD      (STRSPC),HL     ; Bottom of string space / stack top
+        CALL    CLRPTR          ; Clear program and variables
+
+        LD      HL,(STRSPC)
+        LD      DE,0-17         ; BASIC's working-space adjustment
+        ADD     HL,DE
+        LD      DE,(BASTXT)     ; Relocatable program start
+        DEC     DE              ; Preserve original inclusive count
+        LD      A,L
+        SUB     E
+        LD      L,A
+        LD      A,H
+        SBC     A,D
+        LD      H,A
+
+        PUSH    HL              ; Save calculated free-byte count
+        LD      HL,SIGNON
+        CALL    PRS
+        POP     HL
+        CALL    PRNTHL
+        LD      HL,BFREE
+        CALL    PRS
+        JP      WARMST
+        ; ------------------
+
+FULLMSG:
+        .BYTE   "[FULL MEMORY]",CR,LF,0,0
+
+.end