mirror of https://github.com/hsoft/collapseos.git
77 lines
1.3 KiB
NASM
77 lines
1.3 KiB
NASM
; *** CONSTS ***
|
|
|
|
.equ D_DB 0x00
|
|
.equ D_DW 0x01
|
|
.equ D_BAD 0xff
|
|
|
|
; *** CODE ***
|
|
|
|
; 4 bytes per row, fill with zero
|
|
directiveNames:
|
|
.db ".DB", 0
|
|
.db ".DW", 0
|
|
|
|
; This is a list of handlers corresponding to indexes in directiveNames
|
|
directiveHandlers:
|
|
.dw handleDB
|
|
.dw handleDW
|
|
|
|
handleDB:
|
|
push hl
|
|
call toWord
|
|
call readWord
|
|
ld hl, scratchpad
|
|
call parseNumber
|
|
ld a, ixl
|
|
ld (direcData), a
|
|
ld a, 1
|
|
pop hl
|
|
ret
|
|
|
|
handleDW:
|
|
push hl
|
|
call toWord
|
|
call readWord
|
|
ld hl, scratchpad
|
|
call parseNumber
|
|
ld a, ixl
|
|
ld (direcData), a
|
|
ld a, ixh
|
|
ld (direcData+1), a
|
|
ld a, 2
|
|
pop hl
|
|
ret
|
|
|
|
; Reads string in (HL) and returns the corresponding ID (D_*) in A. Sets Z if
|
|
; there's a match.
|
|
getDirectiveID:
|
|
push bc
|
|
push de
|
|
ld b, D_DW+1 ; D_DW is last
|
|
ld c, 4
|
|
ld de, directiveNames
|
|
call findStringInList
|
|
pop de
|
|
pop bc
|
|
ret
|
|
|
|
; Parse directive specified in A (D_* const) with args in (HL) and act in
|
|
; an appropriate manner. If the directive results in writing data at its
|
|
; current location, that data is in (direcData) and A is the number of bytes
|
|
; in it.
|
|
parseDirective:
|
|
push de
|
|
; double A to have a proper offset in directiveHandlers
|
|
add a, a
|
|
ld de, directiveHandlers
|
|
call JUMP_ADDDE
|
|
call JUMP_INTODE
|
|
ld ixh, d
|
|
ld ixl, e
|
|
pop de
|
|
jp (ix)
|
|
|
|
; *** Variables ***
|
|
direcData:
|
|
.fill 2
|