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zasm: make io unit handle PC and output suppression
This commit is contained in:
Virgil Dupras
parent
6547e83f20
commit
ad7428e471
@ -634,7 +634,7 @@ getUpcode:
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bit 7, (ix+3)
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jr z, .absoluteValue ; bit not set? regular byte value,
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; Our argument is a relative address ("e" type in djnz and jr). We have
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; to subtract (ZASM_PC) from it.
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; to subtract (IO_PC) from it.
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; First, check whether we're on first pass. If we are, skip processing
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; below because not having real symbol value makes relative address
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@ -645,7 +645,7 @@ getUpcode:
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; We're on second pass
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push de ; Don't let go of this, that's our dest
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ld de, (ZASM_PC)
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ld de, (IO_PC)
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call intoHL
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dec hl ; what we write is "e-2"
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dec hl
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@ -4,6 +4,9 @@
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; parameter, two blockdevs: One that we can read and seek and one that we can
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; write to (we never seek into it).
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;
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; This unit also has the responsibility of counting the number of written bytes,
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; maintaining IO_PC and of properly disabling output on first pass.
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;
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; zasm doesn't buffers its reads during tokenization, which simplifies its
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; process. However, it also means that it needs, in certain cases, a "putback"
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; mechanism, that is, a way to say "you see that character I've just read? that
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@ -47,7 +50,8 @@
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; see ioPutBack below
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.equ IO_PUTBACK_BUF IO_INCLUDE_HDL+FS_HANDLE_SIZE
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.equ IO_IN_INCLUDE IO_PUTBACK_BUF+1
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.equ IO_RAMEND IO_IN_INCLUDE+1
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.equ IO_PC IO_IN_INCLUDE+1
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.equ IO_RAMEND IO_PC+2
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; *** Code ***
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@ -55,7 +59,7 @@ ioInit:
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xor a
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ld (IO_PUTBACK_BUF), a
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ld (IO_IN_INCLUDE), a
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ret
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jp ioResetPC
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ioGetC:
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ld a, (IO_PUTBACK_BUF)
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@ -101,8 +105,20 @@ ioPutBack:
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ret
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ioPutC:
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push hl
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ld hl, (IO_PC)
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inc hl
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ld (IO_PC), hl
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pop hl
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push af
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call zasmIsFirstPass
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jr z, .skip
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pop af
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ld ix, (IO_OUT_PUTC)
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jp (ix)
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.skip:
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pop af
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ret
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ioSavePos:
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call _ioTell
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@ -117,6 +133,11 @@ ioRewind:
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ld hl, 0
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jr _ioSeek
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ioResetPC:
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ld hl, 0
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ld (IO_PC), hl
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ret
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; always in absolute mode (A = 0)
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_ioSeek:
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call ioInInclude
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@ -43,13 +43,11 @@
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; that when we parse instructions and directive that error out because of a
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; missing symbol, we don't error out and just write down a dummy value.
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.equ ZASM_FIRST_PASS RAMSTART
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; The offset where we currently are with regards to outputting opcodes
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.equ ZASM_PC ZASM_FIRST_PASS+1
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; whether we're in "local pass", that is, in local label scanning mode. During
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; this special pass, ZASM_FIRST_PASS will also be set so that the rest of the
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; code behaves as is we were in the first pass.
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.equ ZASM_LOCAL_PASS ZASM_PC+2
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; What ZASM_PC was when we started our context
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.equ ZASM_LOCAL_PASS ZASM_FIRST_PASS+1
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; What IO_PC was when we started our context
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.equ ZASM_CTX_PC ZASM_LOCAL_PASS+1
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.equ ZASM_RAMEND ZASM_CTX_PC+2
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@ -109,21 +107,11 @@ zasmIsLocalPass:
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cp 1
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ret
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; Increase (ZASM_PC) by A
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incOutputOffset:
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push de
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ld de, (ZASM_PC)
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call addDE
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ld (ZASM_PC), de
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pop de
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ret
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; Repeatedly reads lines from IO, assemble them and spit the binary code in
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; IO. Z is set on success, unset on error. DE contains the last line number to
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; be read (first line is 1).
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zasmParseFile:
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ld de, 0
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ld (ZASM_PC), de
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call ioResetPC
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.loop:
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call parseLine
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ret nz ; error
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@ -142,7 +130,7 @@ zasmParseFile:
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ret
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; Parse next token and accompanying args (when relevant) in I/O, write the
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; resulting opcode(s) through ioPutC and increases (ZASM_PC) by the number of
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; resulting opcode(s) through ioPutC and increases (IO_PC) by the number of
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; bytes written. BC is set to the result of the call to tokenize.
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; Sets Z if parse was successful, unset if there was an error. EOF is not an
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; error.
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@ -166,9 +154,6 @@ _parseInstr:
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or a ; is zero?
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jr z, .error
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ld b, a ; save output byte count
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call incOutputOffset
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call zasmIsFirstPass
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jr z, .success ; first pass, nothing to write
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ld hl, instrUpcode
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.loopInstr:
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ld a, (hl)
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@ -189,9 +174,6 @@ _parseDirec:
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or a ; cp 0
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jr z, .success ; if zero, shortcut through
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ld b, a ; save output byte count
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call incOutputOffset
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call zasmIsFirstPass
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jr z, .success ; first pass, nothing to write
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ld hl, direcData
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.loopDirec:
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ld a, (hl)
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@ -233,7 +215,7 @@ _parseLabel:
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call _endLocalPass
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jr .success
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.registerLabel:
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ld de, (ZASM_PC)
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ld de, (IO_PC)
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call symRegister
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jr nz, .error
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; continue to .success
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@ -248,7 +230,7 @@ _beginLocalPass:
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; remember were I/O was
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call ioSavePos
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; Remember where PC was
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ld hl, (ZASM_PC)
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ld hl, (IO_PC)
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ld (ZASM_CTX_PC), hl
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; Fake first pass
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ld a, 1
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@ -268,7 +250,7 @@ _endLocalPass:
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call ioRecallPos
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; recall PC
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ld hl, (ZASM_CTX_PC)
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ld (ZASM_PC), hl
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ld (IO_PC), hl
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; unfake first pass
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xor a
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ld (ZASM_FIRST_PASS), a
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