From a7693ffd86cc2301f66406efda15fd6c9ac5ceab Mon Sep 17 00:00:00 2001
From: Virgil Dupras <hsoft@hardcoded.net>
Date: Tue, 30 Apr 2019 21:40:22 -0400
Subject: [PATCH] zasm: still inching toward directives

---
 apps/zasm/directive.asm | 27 +++++++++++++++++++++++++++
 apps/zasm/instr.asm     | 11 ++++-------
 apps/zasm/main.asm      | 21 +++++++++++++++------
 apps/zasm/tok.asm       |  2 ++
 4 files changed, 48 insertions(+), 13 deletions(-)
 create mode 100644 apps/zasm/directive.asm

diff --git a/apps/zasm/directive.asm b/apps/zasm/directive.asm
new file mode 100644
index 0000000..6baf14f
--- /dev/null
+++ b/apps/zasm/directive.asm
@@ -0,0 +1,27 @@
+; *** CONSTS ***
+
+D_DB	.equ	0x00
+D_BAD	.equ	0xff
+
+; *** CODE ***
+
+; 4 bytes per row, fill with zero
+directiveNames:
+	.db	".DB", 0
+
+; 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, 1
+	ld	c, 4
+	ld	de, directiveNames
+	call	findStringInList
+	pop	de
+	pop	bc
+	ret
+
+parseDirective:
+	xor	a
+	ret
diff --git a/apps/zasm/instr.asm b/apps/zasm/instr.asm
index 65c0053..6c0bb40 100644
--- a/apps/zasm/instr.asm
+++ b/apps/zasm/instr.asm
@@ -769,15 +769,12 @@ processArg:
 	call	JUMP_UNSETZ
 	ret
 
-; Parse tokens in (tokInstr), (tokArg1) and (tokArg2) and write resulting
-; opcode(s) in (curUpcode). Returns the number of bytes written in A.
-parseTokens:
+; Parse instruction specified in A (I_* const) with args in (tokArg1) and
+; (tokArg2) and write resulting opcode(s) in (curUpcode). Returns the number of
+; bytes written in A.
+parseInstruction:
 	push	hl
 	push	de
-	ld	a, (tokInstr)	; TOK_*
-	cp	TOK_INSTR
-	jr	nz, .error	; Not an instruction, error
-	ld	a, (tokInstr+1)	; I_*
 	ld	hl, tokArg1
 	ld	de, curArg1
 	call	processArg
diff --git a/apps/zasm/main.asm b/apps/zasm/main.asm
index 8f2a980..9d74368 100644
--- a/apps/zasm/main.asm
+++ b/apps/zasm/main.asm
@@ -19,6 +19,11 @@ main:
 .stop:
 	ret
 
+#include "util.asm"
+#include "tok.asm"
+#include "instr.asm"
+#include "directive.asm"
+
 ; Parse line in (HL), write the resulting opcode(s) in (DE) and returns the
 ; number of written bytes in A. Advances HL where tokenization stopped and DE
 ; to where we should write the next upcode.
@@ -26,15 +31,24 @@ parseLine:
 	push	bc
 
 	call	gotoNextNotBlankLine
+	jr	nz, .error
 	push	de
 	ld	de, tokInstr
 	call	tokenize
+	ld	a, (tokInstr)	; TOK_*
+	cp	TOK_BAD
+	jr	z, .error
 	ld	de, tokArg1
 	call	tokenizeInstrArg
 	ld	de, tokArg2
 	call	tokenizeInstrArg
 	pop	de
-	call	parseTokens
+	cp	TOK_INSTR
+	jr	z, .instr
+	jr	.error		; directive not supported yet
+.instr:
+	ld	a, (tokInstr+1)	; I_*
+	call	parseInstruction
 	or	a	; is zero?
 	jr	z, .error
 	ld	b, 0
@@ -51,11 +65,6 @@ parseLine:
 	pop	bc
 	ret
 
-#include "util.asm"
-#include "tok.asm"
-#include "instr.asm"
-#include "directive.asm"
-
 ; *** Variables ***
 
 tokInstr:
diff --git a/apps/zasm/tok.asm b/apps/zasm/tok.asm
index 1dae855..0b71ddc 100644
--- a/apps/zasm/tok.asm
+++ b/apps/zasm/tok.asm
@@ -48,11 +48,13 @@ tokenize:
 	ret
 
 tokenizeInstrArg:
+	push	af
 	xor	a
 	ld	(de), a
 	call	toWord
 	ld	a, 8
 	call	readWord
+	pop	af
 	ret
 
 ; Sets Z is A is ';', CR, LF, or null.