Subversion Repositories Spectranet

;The MIT License

;

;Copyright (c) 2010 Dylan Smith

;

;Permission is hereby granted, free of charge, to any person obtaining a copy

;of this software and associated documentation files (the "Software"), to deal

;in the Software without restriction, including without limitation the rights

;to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

;copies of the Software, and to permit persons to whom the Software is

;furnished to do so, subject to the following conditions:

;

;The above copyright notice and this permission notice shall be included in

;all copies or substantial portions of the Software.

;

;THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

;IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

;FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

;AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

;LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

;OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN

;THE SOFTWARE.

; Handles post-BASIC initialization, allowing the machine to boot

; from a file named boot.zx0.

;

; This routine does the following:

; If SHIFT is held, it tries to load 'boot.zx0' off the currently

; mounted filesystem, using the normal BASIC loader that is contained

; in this module. The return stack is altered such that everything is

; skipped (the (c) message, entry into the editor etc) up to the point

; where lines get interpreted. If 'boot.zx0' is loaded and was saved

; with a LINE parameter, this line is jumped to (by putting CONTINUE

; into the interpreter and setting OLDPPC to NEWPPC). If the LINE

; parameter was not used, the BASIC program loaded is listed.

;

; On error, the stack is restored back to its original state such that

; we re-enter BASIC at the point the (c) message is generated.

.include        "spectranet.inc"

.include        "defs.inc"

.include        "sysvars.inc"

.include        "zxrom.inc"

.include        "zxsysvars.inc"

.include        "ctrlchars.inc"

.include        "../config/config_interface.inc"

.text

.globl F_boot

F_boot:

        call F_shouldboot       ; set zero flag if we should boot

        ret nz                  ; no, do nothing.

        ld hl, STR_bootmsg

        call PRINT42

        ld hl, 0

        add hl, sp              ; hl = sp

        ld sp, (NMISTACK)

        pop de                  ; remove return addr from stack

        ld de, 0x12B4           ; and return to ROM at CALL LINE-SCAN

        push de                 ; and place it on the ZX stack

        push hl                 ; save NMI stack pointer

        rst CALLBAS

        defw 0x16B0             ; SET-MIN routine

        ld a, 0

        rst CALLBAS             ; Open K chan

        defw 0x1601

        ld a, 0xFF              ; ensure ERR_NR is set

        ld (ZX_ERR_NR), a

        ld hl, STR_BOOTDOTZX    ; file to boot with

        ld de, INTERPWKSPC

        ld bc, STR_BOOTDOTZXLEN

        ldir                    ; move to common memory

        ld hl, INTERPWKSPC

        xor a                   ; file type = 0 (BASIC)

        call F_tbas_loader      ; Try to load the file

        jr c, .err1             ; leave here if the loader had an error

        ld hl, (ZX_NEWPPC)      ; get the value of NEWPPC

        ld a, h                 ; Is NEWPPC unset?

        or l

        jr z, .leave1

        ld (ZX_OLDPPC), hl      ; Put in OLDPPC so 'CONTINUE' jumps

        ld a, 0xE8              ; keyword 'CONTINUE'

        rst CALLBAS

        defw 0x0F81             ; ADD-CHAR

        ld a, NEWLINE

        rst CALLBAS

        defw 0x0F81

.leave1:

        pop hl                  ; get NMI stack pointer

        ld sp, hl               ; and restore it

        ret

.err1:

        pop hl                  ; get NMI stack pointer

        pop de                  ; now restore return address

        ld de, 0x1299

        push de

        ld sp, hl               ; and restore it

        ld hl, STR_loaderr      ; or print an error message

        call PRINT42

        ret

;--------------------------------------------------------------------------

; F_shouldboot: See if we should boot (either configured to do so or

; SHIFT is pressed down) Zero flag is set if we should boot, non zero

; return if not.

.globl F_shouldboot

F_shouldboot:

        ld de, ROM_ID           ; section ID

        ld hl, CFG_FINDSECTION  ; go and find it

        rst MODULECALL_NOPAGE

        jr c, .bootonshift2     ; we don't have a section, jump forward.

        ld a, AUTOBOOT          ; get 'autoboot' option

        ld hl, CFG_GETCFBYTE

        rst MODULECALL_NOPAGE

        jr c, .bootonshift2     ; not found, take no action

        and a                   ; if set to zero, then don't autoboot

        jr z, .bootonshift2

        xor a                   ; set the zero flag to signal 'boot'

        ret

.bootonshift2:

        ld bc, 0xFEFE           ; read SHIFT through V

        in a, (c)

        cp 0xBE                 ; SHIFT pressed?

        ret

.data

STR_bootmsg:    defb "Booting...",NEWLINE,0

STR_loaderr:    defb "Error loading boot.zx",NEWLINE,0