# writenum.eas -- write a decimal integer
# SCCSID("@(#)/export/home/staff/mike/src/language/eta/easpit/SCCS/s.writenum.eas	1.2")
#
# Requires: WRITESTR

# Prologue (called with arg).
# Start state				# ... arg addr
>WRITENUM: N0 N2 Halibut		# ... addr NUL arg

N0 H A N0 N1 S S T			# skip to real start if non-zero
N'0 O T N1 N1 Halibut Transfer		# special case for arg=0

# Invariant: stack contains a NUL, then the ASCII codes of the digits
# rendered so far (least significant first), then the remaining part
# of the number being rendered.
>WRITENUMloop: N0 Halibut		# ... addr NUL <digits> arg arg
Address N0 N1 S S Transfer		# if not done, skip a line
S N1 N<WRITENUMdone Transfer		# done: strip NUL, jump to output phase
N10 dividE				# find next digit
N0 N'0 Subtract Subtract		# calculate its ASCII code
# Stack now contains \0 <digits> quotient ASCII(remainder)
# We just need to swap the last two to attain the invariant above.
N1 Halibut				# swap
N1 N<WRITENUMloop Transfer		# next iteration

# Call existing code to output the accumulated digits.
>WRITENUMdone: A N1 N<WRITESTR Transfer
# Epilogue: return to the stacked address
N1 N1 Halibut Transfer