Chapter 2
C Language Reference
2-36
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Figures 2-6 through 2-8 show how the conversion macros are named.
Notice that macro names have no embedded spaces.
Figure 2-6.
AutoCode/C Conversion Macros for Fixed-to-Fixed Conversions
For example, the macro to convert an unsigned 8-bit number to a signed
8-bit number with a shift of
rp
bits, and with overflow protection is:
sbALIGNubp(n,rp)
n = Fixed-point operand to align
sr wr ALIGN so wo p q(n, rp)
rp = Number of bits to shift
q = optional answer quantization (r, c, or f)
p = Overflow protection (optional)
wo = Operand wordsize (b=byte, s=short, l=long)
so = Operand sign (u=unsigned, s=signed)
ALIGN (indicates conversion)
wr = Result wordsize (b=byte,
s=short, l=long)
sr = Result sign (u=unsigned, s=signed)
(if rp < 0, perform a left-shift;
if rp > 0, perform a right-shift)
r = round the answer
c = ceiling the answer
f = floor the answer
default (no r, c, or f) is truncate the answer
NOTE: The operand wordsize must be equal
to or larger than the result wordsize
(see NOTE above)
