diff --git a/apps/zasm/io.asm b/apps/zasm/io.asm
index c9bee13..3fa0da0 100644
--- a/apps/zasm/io.asm
+++ b/apps/zasm/io.asm
@@ -7,6 +7,11 @@
 ; This unit also has the responsibility of counting the number of written bytes,
 ; maintaining IO_PC and of properly disabling output on first pass.
 ;
+; On top of that, this unit has the responsibility of keeping track of the
+; current lineno. Whenever GetC is called, we check if the fetched char is a
+; newline. If it is, we increase our lineno. This unit is the best place to
+; keep track of this because we have to handle ioRecallPos.
+;
 ; zasm doesn't buffers its reads during tokenization, which simplifies its
 ; process. However, it also means that it needs, in certain cases, a "putback"
 ; mechanism, that is, a way to say "you see that character I've just read? that
@@ -50,8 +55,12 @@
 ; see ioPutBack below
 .equ	IO_PUTBACK_BUF	IO_INCLUDE_HDL+FS_HANDLE_SIZE
 .equ	IO_IN_INCLUDE	IO_PUTBACK_BUF+1
-.equ	IO_PC	IO_IN_INCLUDE+1
-.equ	IO_RAMEND	IO_PC+2
+.equ	IO_PC		IO_IN_INCLUDE+1
+; Current lineno in top-level file
+.equ	IO_LINENO	IO_PC+2
+; Line number (can be top-level or include) when ioSavePos was last called.
+.equ	IO_SAVED_LINENO	IO_LINENO+2
+.equ	IO_RAMEND	IO_SAVED_LINENO+2
 
 ; *** Code ***
 
@@ -59,7 +68,7 @@ ioInit:
 	xor	a
 	ld	(IO_PUTBACK_BUF), a
 	ld	(IO_IN_INCLUDE), a
-	jp	ioResetPC
+	jp	ioResetCounters
 
 ioGetC:
 	ld	a, (IO_PUTBACK_BUF)
@@ -89,7 +98,17 @@ ioGetC:
 .normalmode:
 	; normal mode, read from IN stream
 	ld	ix, (IO_IN_GETC)
-	jp	(ix)
+	call	_callIX
+	cp	0x0a		; newline
+	ret	nz		; not newline? return
+	; inc current lineno
+	push	hl
+	ld	hl, IO_LINENO
+	inc	(hl)
+	pop	hl
+	cp	a		; ensure Z
+	ret
+
 .getback:
 	push	af
 	xor	a
@@ -97,6 +116,10 @@ ioGetC:
 	pop	af
 	ret
 
+_callIX:
+	jp	(ix)
+	ret
+
 ; Put back non-zero character A into the "ioGetC stack". The next ioGetC call,
 ; instead of reading from IO_IN_GETC, will return that character. That's the
 ; easiest way I found to handle the readWord/gotoNextLine problem.
@@ -121,21 +144,27 @@ ioPutC:
 	ret
 
 ioSavePos:
+	ld	hl, (IO_LINENO)
+	ld	(IO_SAVED_LINENO), hl
 	call	_ioTell
 	ld	(IO_SAVED_POS), hl
 	ret
 
 ioRecallPos:
+	ld	hl, (IO_SAVED_LINENO)
+	ld	(IO_LINENO), hl
 	ld	hl, (IO_SAVED_POS)
 	jr	_ioSeek
 
 ioRewind:
-	ld	hl, 0
+	call	ioResetCounters		; sets HL to 0
 	jr	_ioSeek
 
-ioResetPC:
+ioResetCounters:
 	ld	hl, 0
 	ld	(IO_PC), hl
+	ld	(IO_LINENO), hl
+	ld	(IO_SAVED_LINENO), hl
 	ret
 
 ; always in absolute mode (A = 0)
@@ -186,3 +215,7 @@ ioOpenInclude:
 	cp	a		; ensure Z
 	ret
 
+; Return current lineno in HL
+ioLineNo:
+	ld	hl, (IO_LINENO)
+	ret
diff --git a/apps/zasm/main.asm b/apps/zasm/main.asm
index 34684be..02f2763 100644
--- a/apps/zasm/main.asm
+++ b/apps/zasm/main.asm
@@ -16,7 +16,8 @@
 .equ	ZASM_RAMEND		ZASM_ORG+2
 
 ; Read file through blockdev ID in H and outputs its upcodes through blockdev
-; ID in L.
+; ID in L. HL is set to the last lineno to be read.
+; Sets Z on success, unset on error. On error, A contains an error code (ERR_*)
 zasmMain:
 	; Init I/O
 	ld	a, h
@@ -38,13 +39,13 @@ zasmMain:
 	ld	a, 1
 	ld	(ZASM_FIRST_PASS), a
 	call	zasmParseFile
-	ret	nz
+	jr	nz, .end
 	; Second pass
-	call	ioRewind
 	xor	a
 	ld	(ZASM_FIRST_PASS), a
 	call	zasmParseFile
-	ret
+.end:
+	jp	ioLineNo		; --> HL, returns
 
 ; Sets Z according to whether we're in first pass.
 zasmIsFirstPass:
@@ -76,7 +77,7 @@ zasmGetPC:
 ; IO. Z is set on success, unset on error. DE contains the last line number to
 ; be read (first line is 1).
 zasmParseFile:
-	call	ioResetPC
+	call	ioRewind
 .loop:
 	call	parseLine
 	ret	nz		; error
diff --git a/tools/emul/zasm/zasm.bin b/tools/emul/zasm/zasm.bin
index b7b0c76..d0d68a3 100644
Binary files a/tools/emul/zasm/zasm.bin and b/tools/emul/zasm/zasm.bin differ
diff --git a/tools/emul/zasm/zasm.c b/tools/emul/zasm/zasm.c
index f3bc0fb..10508f0 100644
--- a/tools/emul/zasm/zasm.c
+++ b/tools/emul/zasm/zasm.c
@@ -190,7 +190,8 @@ int main()
     fflush(stdout);
     int res = cpu.R1.br.A;
     if (res != 0) {
-        fprintf(stderr, "Error %d\n", res);
+        int lineno = cpu.R1.wr.HL;
+        fprintf(stderr, "Error %d on line %d\n", res, lineno);
     }
     return res;
 }