extra code

section_1/float/away.s

@@ -0,0 +1,55 @@
+        .global main
+        .text
+        .align  2
+
+fv      .req    d20
+
+/*	There is  no  round-away-from-zero instruction. Instead, we
+	duplicate the C++ version of this function (but with better
+	performance).
+*/
+RoundAwayFromZero:
+		fcmp	d0, 0
+		ble		1f
+		// Value is positive, truncate up.
+		frintp	d0, d0
+		b 		2f
+1:		// Value is negative, truncate down.
+		frintm	d0, d0
+2:		fcvtzs	x0, d0
+		ret
+
+main:   str     x30, [sp, -16]!
+		str		fv, [sp, -16]!
+		// Initialize fv with 5.1
+		ldr		x0, =flit
+		ldr		fv, [x0]
+
+		fmov	d0, fv             // Load up fv for RoundAwayFromZero
+		bl		RoundAwayFromZero  // And call the function
+		mov		x1, x0             // Place result for printing
+		fmov	d0, fv             // Place fv for printing
+		ldr		x0, =fmt1          // Place address of fmt1 string
+		bl		printf             // And print
+
+		fmov	d0, fv             // Load up fv to make it negative
+		fneg	d0, d0             // Floating point negation
+		bl		RoundAwayFromZero  // Call the function
+		mov		x1, x0             // Place for printing
+		fmov	d0, fv             // Recreate negative value
+		fneg	d0, d0             // Positioned for printing
+		ldr		x0, =fmt2          // Place address of fmt2 string
+		bl		printf             // And print
+
+		ldr		fv, [sp], 16
+        ldr     x30, [sp], 16
+        mov     w0, wzr
+        ret
+
+		.data
+		
+flit:	.double	5.1
+fmt1:	.asciz	"%4.1f away from zero (should be  6): %2d\n"
+fmt2:	.asciz	"%4.1f away from zero (should be -6): %2d\n"
+
+		.end