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collapseos/apps/zasm/directive.asm
2019-06-15 20:01:17 -04:00

271 lines
4.2 KiB
NASM

; *** CONSTS ***
.equ D_DB 0x00
.equ D_DW 0x01
.equ D_EQU 0x02
.equ D_ORG 0x03
.equ D_FIL 0x04
.equ D_OUT 0x05
.equ D_INC 0x06
.equ D_BAD 0xff
; *** Variables ***
.equ DIREC_SCRATCHPAD DIREC_RAMSTART
.equ DIREC_RAMEND DIREC_SCRATCHPAD+SCRATCHPAD_SIZE
; *** CODE ***
; 4 bytes per row, fill with zero
directiveNames:
.db ".DB", 0
.db ".DW", 0
.db ".EQU"
.db ".ORG"
.db ".FIL"
.db ".OUT"
.db "#inc"
; This is a list of handlers corresponding to indexes in directiveNames
directiveHandlers:
.dw handleDB
.dw handleDW
.dw handleEQU
.dw handleORG
.dw handleFIL
.dw handleOUT
.dw handleINC
handleDB:
push hl
.loop:
call readWord
jr nz, .badfmt
ld hl, scratchpad
call enterDoubleQuotes
jr z, .stringLiteral
call parseExpr
jr nz, .badarg
push ix \ pop hl
ld a, h
or a ; cp 0
jr nz, .overflow ; not zero? overflow
ld a, l
call ioPutC
jr nz, .ioError
.stopStrLit:
call readComma
jr z, .loop
cp a ; ensure Z
pop hl
ret
.ioError:
ld a, SHELL_ERR_IO_ERROR
jr .error
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
jr .error
.overflow:
ld a, ERR_OVFL
.error:
call unsetZ
pop hl
ret
.stringLiteral:
ld a, (hl)
inc hl
or a ; when we encounter 0, that was what used to
jr z, .stopStrLit ; be our closing quote. Stop.
; Normal character, output
call ioPutC
jr .stringLiteral
handleDW:
push hl
.loop:
call readWord
jr nz, .badfmt
ld hl, scratchpad
call parseExpr
jr nz, .badarg
push ix \ pop hl
ld a, l
call ioPutC
ld a, h
call ioPutC
call readComma
jr z, .loop
cp a ; ensure Z
pop hl
ret
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
.error:
call unsetZ
pop hl
ret
handleEQU:
call zasmIsLocalPass ; Are we in local pass? Then ignore all .equ.
jr z, .skip ; they mess up duplicate symbol detection.
push hl
push de
push bc
; Read our constant name
call readWord
jr nz, .badfmt
; We can't register our symbol yet: we don't have our value!
; Let's copy it over.
ld de, DIREC_SCRATCHPAD
ld bc, SCRATCHPAD_SIZE
ldir
; Now, read the value associated to it
call readWord
jr nz, .badfmt
ld hl, scratchpad
call parseExpr
jr nz, .badarg
ld hl, DIREC_SCRATCHPAD
push ix \ pop de
call symRegister ; A and Z set
jr .end
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
.error:
call unsetZ
.end:
pop bc
pop de
pop hl
ret
.skip:
; consume args and return
call readWord
jp readWord
handleORG:
call readWord
jr nz, .badfmt
call parseExpr
jr nz, .badarg
push ix \ pop hl
call zasmSetOrg
cp a ; ensure Z
ret
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
.error:
call unsetZ
ret
handleFIL:
call readWord
jr nz, .badfmt
call parseExpr
jr nz, .badarg
push bc
push ix \ pop bc
xor a
ld b, c
.loop:
call ioPutC
djnz .loop
cp a ; ensure Z
pop bc
ret
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
.error:
call unsetZ
ret
handleOUT:
push hl
; Read our expression
call readWord
jr nz, .badfmt
call zasmIsFirstPass ; No .out during first pass
jr z, .end
ld hl, scratchpad
call parseExpr
jr nz, .badarg
push ix \ pop hl
ld a, h
out (ZASM_DEBUG_PORT), a
ld a, l
out (ZASM_DEBUG_PORT), a
jr .end
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badarg:
ld a, ERR_BAD_ARG
.error:
call unsetZ
.end:
pop hl
ret
handleINC:
call readWord
jr nz, .badfmt
; HL points to scratchpad
call enterDoubleQuotes
jr nz, .badfmt
call ioOpenInclude
jr nz, .badfn
cp a ; ensure Z
ret
.badfmt:
ld a, ERR_BAD_FMT
jr .error
.badfn:
ld a, ERR_FILENOTFOUND
.error:
call unsetZ
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_INC+1 ; D_INC 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 I/O and act in
; an appropriate manner. If the directive results in writing data at its
; current location, that data is directly written through ioPutC.
; Each directive has the same return value pattern: Z on success, not-Z on
; error, A contains the error number (ERR_*).
parseDirective:
push de
; double A to have a proper offset in directiveHandlers
add a, a
ld de, directiveHandlers
call addDE
call intoDE
push de \ pop ix
pop de
jp (ix)