apps/zasm/instr.asm

@@ -248,13 +248,16 @@ parseArg:
 
 ; Returns, with Z, whether A is a groupId
 isGroupId:
-	or	a
-	jp	z, unsetZ	; not a group
-	cp	0xd		; max group id + 1
-	jp	nc, unsetZ	; >= 0xd? not a group
+	cp	0xc	; max group id + 1
+	jr	nc, .notgroup	; >= 0xc? not a group
+	cp	0
+	jr	z, .notgroup	; 0? not supposed to happen. something's wrong.
 	; A is a group. ensure Z is set
 	cp	a
 	ret
+.notgroup:
+	call	unsetZ
+	ret
 
 ; Find argspec A in group id H.
 ; Set Z according to whether we found the argspec
@@ -334,7 +337,7 @@ findInGroup:
 ; If it's not this, then we check if it's a numerical arg.
 ; If A is a group ID, we do something else: we check that (HL) exists in the
 ; groupspec (argGrpTbl). Moreover, we go and write the group's "value" (index)
-; in (HL+1). This will save us significant processing later in spitUpcode.
+; in (HL+1). This will save us significant processing later in getUpcode.
 ; Set Z according to whether we match or not.
 matchArg:
 	cp	(hl)
@@ -342,16 +345,11 @@ matchArg:
 	; not an exact match. Before we continue: is A zero? Because if it is,
 	; we have to stop right here: no match possible.
 	or	a
-	jr	nz, .skip	; not a zero, we can continue
+	jr	nz, .checkIfNumber	; not a zero, we can continue
 	; zero, stop here
-	cp	1			; unset Z
+	call	unsetZ
 	ret
-.skip:
-	; Alright, let's start with a special case. Is it part of the special
-	; "BIT" group, 0xc? If yes, we actually expect a number, which will
-	; then be ORed like a regular group index.
-	cp	0xc
-	jr	z, .expectsBIT
+.checkIfNumber:
 	; not an exact match, let's check for numerical constants.
 	call	upcase
 	call	checkNOrM
@@ -365,21 +363,6 @@ matchArg:
 	cp	(hl)
 	ret			; whether we match or not, the result of Z is
 				; the good one.
-.expectsBIT:
-	ld	a, (hl)
-	cp	'N'
-	inc	hl
-	ld	a, (hl)
-	dec	hl
-	cp	8
-	jr	c, .isBit	; A < 8
-	; not a bit
-	or	a		; unset Z
-	ret
-.isBit:
-	cp	a		; set Z
-	ret
-
 .notNumber:
 	; A bit of a delicate situation here: we want A to go in H but also
 	; (HL) to go in A. If not careful, we overwrite each other. EXX is
@@ -424,8 +407,8 @@ matchPrimaryRow:
 ; *** Special opcodes ***
 ; The special upcode handling routines below all have the same signature.
 ; Instruction row is at IX and we're expected to perform the same task as
-; spitUpcode. The number of bytes, however, must go in C instead of A
-; No need to preserve HL, DE, BC and IX: it's handled by spitUpcode already.
+; getUpcode. The number of bytes, however, must go in C instead of A
+; No need to preserve HL, DE, BC and IX: it's handled by getUpcode already.
 
 ; Handle like a regular "JP (IX+d)" except that we refuse any displacement: if
 ; a displacement is specified, we error out.
@@ -461,6 +444,28 @@ handleBIT:
 	ld	c, 0
 	jp	unsetZ
 
+handleBITHL:
+	ld	b, 0b01000110
+	jr	_handleBITHL
+handleSETHL:
+	ld	b, 0b11000110
+	jr	_handleBITHL
+handleRESHL:
+	ld	b, 0b10000110
+_handleBITHL:
+	call	handleBIT
+	ret	nz		; error
+	ld	a, 0xcb		; first upcode
+	ld	(INS_UPCODE), a
+	ld	a, (INS_CURARG1+1)	; 0-7
+	rla
+	rla
+	rla
+	or	b		; 2nd upcode
+	ld	(INS_UPCODE+1), a
+	ld	c, 2
+	ret
+
 handleBITIX:
 	ld	a, 0xdd
 	ld	b, 0b01000110
@@ -620,9 +625,11 @@ handleLDrr:
 	ret
 
 ; Compute the upcode for argspec row at (DE) and arguments in curArg{1,2} and
-; writes the resulting upcode to IO.
-; A is zero, with Z set, on success. A is non-zero, with Z unset, on error.
-spitUpcode:
+; writes the resulting upcode in INS_UPCODE. A is the number if bytes written
+; to INS_UPCODE.
+; A is zero on error. The only thing that can go wrong in this routine is
+; overflow.
+getUpcode:
 	push	ix
 	push	de
 	push	hl
@@ -638,7 +645,7 @@ spitUpcode:
 	ld	h, (ix+5)
 	call	callHL
 	; We have our result written in INS_UPCODE and C is set.
-	jp	.writeIO
+	jp	.end
 
 .normalInstr:
 	; we begin by writing our "base upcode", which can be one or two bytes
@@ -727,7 +734,7 @@ spitUpcode:
 	call	checknmxy
 	jr	z, .withByte
 	; nope, no number, alright, we're finished here
-	jr	.writeIO
+	jr	.end
 .withByte:
 	inc	hl
 	; HL points to our number (LSB), with (HL+1) being our MSB which should
@@ -744,7 +751,7 @@ spitUpcode:
 	; verification falsely fail.
 	inc	c		; one extra byte is written
 	call	zasmIsFirstPass
-	jr	z, .writeIO
+	jr	z, .end
 
 	; We're on second pass
 	push	de		; Don't let go of this, that's our dest
@@ -774,7 +781,7 @@ spitUpcode:
 	or	a		; cp 0
 	jr	nz, .numberTruncated	; if A is anything but zero, we're out
 					; of bounds.
-	jr	.writeIO
+	jr	.end
 
 .absoluteValue:
 	; verify that the MSB in argument is zero
@@ -787,7 +794,7 @@ spitUpcode:
 	ldi
 	pop	bc
 	inc	c
-	jr	.writeIO
+	jr	.end
 
 .withWord:
 	inc	hl	; HL now points to LSB
@@ -798,28 +805,12 @@ spitUpcode:
 	pop	bc
 	inc	c		; two extra bytes are written
 	inc	c
-	; to writeIO
-.writeIO:
-	; Let's write INS_UPCODE to IO
-	ld	b, c		; save output byte count
-	ld	hl, INS_UPCODE
-.loopWrite:
-	ld	a, (hl)
-	call	ioPutB
-	jr	nz, .ioError
-	inc	hl
-	djnz	.loopWrite
-	; Z is set by INC HL
 	jr	.end
 .numberTruncated:
-	; Z already unset
-	ld	a, ERR_OVFL
-	jr	.end
-.ioError:
-	; Z already unset
-	ld	a, SHELL_ERR_IO_ERROR
-	; continue to .end
+	; problem: not zero, so value is truncated. error
+	ld	c, 0
 .end:
+	ld	a, c
 	pop	bc
 	pop	hl
 	pop	de
@@ -890,10 +881,26 @@ parseInstruction:
 .match:
 	; We have our matching instruction row. We're getting pretty near our
 	; goal here!
-	call	spitUpcode
-	jr	.end		; Z and A set properly, even on error
+	call	getUpcode
+	or	a	; is zero?
+	jr	z, .overflow
+	ld	b, a		; save output byte count
+	ld	hl, INS_UPCODE
+.loopWrite:
+	ld	a, (hl)
+	call	ioPutB
+	jr	nz, .ioError
+	inc	hl
+	djnz	.loopWrite
+	cp	a	; ensure Z
+	jr	.end
+.ioError:
+	ld	a, SHELL_ERR_IO_ERROR
+	jr	.error
+.overflow:
+	ld	a, ERR_OVFL
+	jr	.error
 .badfmt:
-	; Z already unset
 	ld	a, ERR_BAD_FMT
 .error:
 	; A is set to error already
@@ -976,10 +983,6 @@ argGrpCC:
 argGrpABCDEHL:
 	.db	"BCDEHL_A"	; 0xb
 
-; SPECIAL GROUP "BIT": 0xc
-; When special group "0xc" shows up in argspec, it means: accept a number
-; between 0 and 7. The value is then treated like a regular group value.
-
 ; Each row is 4 bytes wide, fill with zeroes
 instrNames:
 	.db "ADC", 0
@@ -1085,7 +1088,7 @@ instrTBl:
 	.db I_AND, 'n', 0,   0,    0xe6		, 0	; AND n
 	.db I_AND, 'x', 0,   0,    0xdd, 0xa6		; AND (IX+d)
 	.db I_AND, 'y', 0,   0,    0xfd, 0xa6		; AND (IY+d)
-	.db I_BIT, 0xc, 'l', 0x43, 0xcb, 0b01000110	; BIT b, (HL)
+	.db I_BIT, 'n', 'l', 0x20 \ .dw handleBITHL	; BIT b, (HL)
 	.db I_BIT, 'n', 'x', 0x20 \ .dw handleBITIX	; BIT b, (IX+d)
 	.db I_BIT, 'n', 'y', 0x20 \ .dw handleBITIY	; BIT b, (IY+d)
 	.db I_BIT, 'n', 0xb, 0x20 \ .dw handleBITR	; BIT b, r
@@ -1198,7 +1201,7 @@ instrTBl:
 	.db I_PUSH,'X', 0,   0,    0xdd, 0xe5		; PUSH IX
 	.db I_PUSH,'Y', 0,   0,    0xfd, 0xe5		; PUSH IY
 	.db I_PUSH,0x1, 0,   4,    0b11000101	, 0	; PUSH qq
-	.db I_RES, 0xc, 'l', 0x43, 0xcb, 0b10000110	; RES b, (HL)
+	.db I_RES, 'n', 'l', 0x20 \ .dw handleRESHL	; RES b, (HL)
 	.db I_RES, 'n', 'x', 0x20 \ .dw handleRESIX	; RES b, (IX+d)
 	.db I_RES, 'n', 'y', 0x20 \ .dw handleRESIY	; RES b, (IY+d)
 	.db I_RES, 'n', 0xb, 0x20 \ .dw handleRESR	; RES b, r
@@ -1218,7 +1221,7 @@ instrTBl:
 	.db I_SBC, 'A', 0xb, 0,    0b10011000	, 0	; SBC A, r
 	.db I_SBC,'h',0x3,0x44,    0xed, 0b01000010	; SBC HL, ss
 	.db I_SCF, 0,   0,   0,    0x37		, 0	; SCF
-	.db I_SET, 0xc, 'l', 0x43, 0xcb, 0b11000110	; SET b, (HL)
+	.db I_SET, 'n', 'l', 0x20 \ .dw handleSETHL	; SET b, (HL)
 	.db I_SET, 'n', 'x', 0x20 \ .dw handleSETIX	; SET b, (IX+d)
 	.db I_SET, 'n', 'y', 0x20 \ .dw handleSETIY	; SET b, (IY+d)
 	.db I_SET, 'n', 0xb, 0x20 \ .dw handleSETR	; SET b, r

apps/zasm/io.asm

@@ -88,9 +88,8 @@ ioGetB:
 	; We have newline. Increase lineno and return (the rest of the
 	; processing below isn't needed.
 	push	hl
-	ld	hl, (IO_INC_LINENO)
-	inc	hl
-	ld	(IO_INC_LINENO), hl
+	ld	hl, IO_INC_LINENO
+	inc	(hl)
 	pop	hl
 	ret