diff --git a/mach/arm/as/mach0.c b/mach/arm/as/mach0.c
index 855541a15..1853f8de4 100644
--- a/mach/arm/as/mach0.c
+++ b/mach/arm/as/mach0.c
@@ -8,9 +8,6 @@
 #define WORDS_REVERSED
 #define BYTES_REVERSED
 */
-#undef valu_t
-#define valu_t 	long
-
 #undef ADDR_T
 #define ADDR_T long
 
diff --git a/mach/i386/as/mach0.c b/mach/i386/as/mach0.c
index 6fb5358d5..63f719565 100644
--- a/mach/i386/as/mach0.c
+++ b/mach/i386/as/mach0.c
@@ -11,8 +11,6 @@
 #define	LISTING		/* enable listing facilities */
 #define RELOCATION	/* generate relocation info */
 
-#undef valu_t
-#define valu_t long
 #undef ADDR_T
 #define ADDR_T long
 
diff --git a/mach/i86/as/mach0.c b/mach/i86/as/mach0.c
index 1c47e4874..fc69730c9 100644
--- a/mach/i86/as/mach0.c
+++ b/mach/i86/as/mach0.c
@@ -12,9 +12,6 @@
 #define RELOCATION	/* generate relocation info */
 #define DEBUG 0
 
-#undef valu_t
-#define valu_t long
-
 #undef ALIGNWORD
 #define ALIGNWORD 2
 #undef ALIGNSECT
diff --git a/mach/m68020/as/mach0.c b/mach/m68020/as/mach0.c
index 498620c0e..8e79b89a6 100644
--- a/mach/m68020/as/mach0.c
+++ b/mach/m68020/as/mach0.c
@@ -14,8 +14,6 @@
 #define RELOCATION		/* generate relocatable code */
 #define DEBUG 0
 
-#undef	valu_t
-#define	valu_t		long
 #undef	ADDR_T
 #define	ADDR_T		long
 
diff --git a/mach/m68k2/as/mach0.c b/mach/m68k2/as/mach0.c
index 72845b0be..62878f7dc 100644
--- a/mach/m68k2/as/mach0.c
+++ b/mach/m68k2/as/mach0.c
@@ -17,8 +17,6 @@
 
 #define Xfit(f)		if (!(f)) Xnofit();
 
-#undef	valu_t
-#define	valu_t		long
 #undef	ADDR_T
 #define	ADDR_T		long
 
diff --git a/mach/mips/as/mach0.c b/mach/mips/as/mach0.c
index edce6640b..8aef3d697 100644
--- a/mach/mips/as/mach0.c
+++ b/mach/mips/as/mach0.c
@@ -8,9 +8,6 @@
 #define RELOCATION          /* generate relocatable code */
 #define DEBUG 0
 
-#undef valu_t
-#define valu_t int32_t
-
 #undef ADDR_T
 #define ADDR_T uint32_t
 
diff --git a/mach/ns/as/mach0.c b/mach/ns/as/mach0.c
index e4ba505ae..218f7c76e 100644
--- a/mach/ns/as/mach0.c
+++ b/mach/ns/as/mach0.c
@@ -10,8 +10,6 @@
 #define	THREE_PASS	/* branch and offset optimization */
 #define	LISTING		/* enable listing facilities */
 
-#undef	valu_t
-#define valu_t		long
 #undef	ADDR_T
 #define	ADDR_T		long
 #undef	ALIGNSECT
diff --git a/mach/powerpc/as/mach0.c b/mach/powerpc/as/mach0.c
index 1c2051753..b6eec8f2d 100644
--- a/mach/powerpc/as/mach0.c
+++ b/mach/powerpc/as/mach0.c
@@ -10,9 +10,6 @@
 #define RELOCATION          /* generate relocatable code */
 #define DEBUG 0
 
-#undef valu_t
-#define valu_t int32_t
-
 #undef ADDR_T
 #define ADDR_T uint32_t
 
diff --git a/mach/proto/as/comm0.h b/mach/proto/as/comm0.h
index 03b48f75e..5ef226be6 100644
--- a/mach/proto/as/comm0.h
+++ b/mach/proto/as/comm0.h
@@ -58,7 +58,8 @@ _include	<string.h>
 
 #define	GENLAB		"I"		/* compiler generated labels */
 
-#define	valu_t		long		/* type of expression values */
+#define	valu_t		int64_t		/* type of expression values */
+#define	uvalu_t		uint64_t	/* unsigned valu_t */
 #define	ADDR_T		unsigned short	/* type of dot */
 #define	word_t		short		/* type of keyword value */
 /*
diff --git a/mach/proto/as/comm2.y b/mach/proto/as/comm2.y
index 1e28979fa..83d74f5fc 100644
--- a/mach/proto/as/comm2.y
+++ b/mach/proto/as/comm2.y
@@ -22,7 +22,6 @@ static item_t	*last_it, *o_it;
 %union {
 	word_t	y_word;
 	valu_t	y_valu;
-	int64_t	y_valu8;
 	expr_t	y_expr;
 	item_t	*y_item;
 #ifdef ASLD
@@ -44,7 +43,7 @@ static item_t	*last_it, *o_it;
 %token NUMBER2
 %token NUMBER3
 %token NUMBER4
-%token <y_valu8> NUMBER8
+%token <y_valu> NUMBER8
 %token NUMBERF
 %token DOT
 %token EXTERN
@@ -77,7 +76,6 @@ static item_t	*last_it, *o_it;
 %nonassoc '~'
 
 %type <y_valu> absexp optabs1 optabs2
-%type <y_valu8> datum8
 %type <y_expr> expr
 %type <y_item> id_fb
 
@@ -285,17 +283,10 @@ datalist
 			}
 	;
 
-/* datum8 isn't expr, because int64_t may be wider than valu_t. */
-datum8	:	NUMBER8
-			{	$$ = $1;}
-	|	'-' NUMBER8
-			{	$$ = -$2;}
-	;
-
 data8list
-	:	datum8
+	:	absexp
 			{	emit8($1);}
-	|	data8list ',' datum8
+	|	data8list ',' absexp
 			{	emit8($3);}
 	;
 
diff --git a/mach/proto/as/comm5.c b/mach/proto/as/comm5.c
index 2987aedb2..ee877120c 100644
--- a/mach/proto/as/comm5.c
+++ b/mach/proto/as/comm5.c
@@ -121,7 +121,7 @@ void putval(int c)
 			v = yylval.y_valu;
 			goto putnum;
 		case NUMBER8:
-			v = yylval.y_valu8;
+			v = yylval.y_valu;
 			for (n = 0; n < sizeof(v); n++)
 			{
 				if (v == 0)
@@ -132,7 +132,7 @@ void putval(int c)
 				c = NUMBER0 + n;
 			else
 				n = 8;
-			v = yylval.y_valu8;
+			v = yylval.y_valu;
 		putnum:
 			putc(c, tempfile);
 			putc(c >> 8, tempfile);
@@ -236,10 +236,7 @@ int getval(int c)
 				v <<= 8;
 				v |= getc(tempfile);
 			}
-			if (c == NUMBER8)
-				yylval.y_valu8 = v;
-			else
-				yylval.y_valu = v;
+			yylval.y_valu = v;
 			return (c);
 		case IDENT:
 		case FBSYM:
@@ -421,7 +418,7 @@ static void need_stringbuf()
 
 static int innumber(int c)
 {
-	uint64_t uv;
+	uvalu_t uv;
 	char* p;
 	int radix;
 	static char num[40 + 1];
@@ -473,7 +470,7 @@ static int innumber(int c)
 			serror("digit exceeds radix");
 		uv = uv * radix + c;
 	}
-	yylval.y_valu8 = uv; /* signed = unsigned */
+	yylval.y_valu = uv; /* signed = unsigned */
 	return (NUMBER8);
 
 floatconstant:
diff --git a/mach/vax4/as/mach0.c b/mach/vax4/as/mach0.c
index 531de3a15..97f8ca93f 100644
--- a/mach/vax4/as/mach0.c
+++ b/mach/vax4/as/mach0.c
@@ -12,8 +12,6 @@
 #define LISTING
 #define RELOCATION
 
-#undef valu_t
-#define valu_t long
 #undef word_t
 #define word_t long
 #undef ADDR_T
diff --git a/mach/vc4/as/mach0.c b/mach/vc4/as/mach0.c
index 2df70061c..0e92645ea 100644
--- a/mach/vc4/as/mach0.c
+++ b/mach/vc4/as/mach0.c
@@ -10,9 +10,6 @@
 #define RELOCATION          /* generate relocatable code */
 #define DEBUG 0
 
-#undef valu_t
-#define valu_t long
-
 #undef ADDR_T
 #define ADDR_T long
 
diff --git a/mach/z8000/as/mach0.c b/mach/z8000/as/mach0.c
index 15b97913b..c731d5a50 100644
--- a/mach/z8000/as/mach0.c
+++ b/mach/z8000/as/mach0.c
@@ -14,7 +14,5 @@
 #define ASLD
 #undef ALIGNSECT
 #define ALIGNSECT	2
-#undef valu_t
-#define valu_t long
 #undef ADDR_T
 #define ADDR_T long
diff --git a/man/uni_ass.6 b/man/uni_ass.6
index 558fae2de..572ec0ff1 100644
--- a/man/uni_ass.6
+++ b/man/uni_ass.6
@@ -154,9 +154,8 @@ if the number starts with '0x' it is hexadecimal else
     if the number starts with '0' it is octal else
         it's decimal.
 .fi
-The range of numbers depends on the machine.
-A rule of the thumb is that the width of the machine's registers
-the same is as the number of bits allowed in numbers.
+The width of numbers is at least 64 bits, so the .data8 pseudo may
+accept the full range of 8-byte values.
 .IP comment
 The character '!' denotes the start of comment, every character
 up to the next newline is skipped.
@@ -206,11 +205,9 @@ This is not followed by automatic alignment.
 .Pu ".data4 \fIexpression\fP [, \fIexpression\fP]*"
 Initialize a sequence of longs (4-byte values).
 This is not followed by automatic alignment.
-.Pu ".data8 \fIliteralint\fP [, \fIliteralint\fP]*"
+.Pu ".data8 \fIexpression\fP [, \fIexpression\fP]*"
 Initialize a sequence of long longs (8-byte values).
-This accepts only literal integers, not symbols nor expressions; but
-a \fIliteralint\fP may be any signed or unsigned 8-byte integer, even
-if it is outside the usual range for the machine.
+The expressions must be absolute.
 This is not followed by automatic alignment.
 .Pu ".dataf4 \fIliteralfloat\fP [, \fIliteralfloat\fP]*"
 Initialize a sequence of floats (4-byte values).