_2E8F_PF_MEDIUM (X isn't a small integer or a pure fraction; X is more than one but less than 2**27. It is therefore necessary to count how many of the binary digits should be considered as preceding the fractional point. N in themagnitude counter indicates by how many powers of ten, if any, Xhas been reduced; iX is the last value on the stack): - call 2FBA FETCH TWO with the pointers switched, to getiX into L'D'E'DE - set the hi bit of D'; this corrects the mantissa to a true mantissa - get the exponent from L' - subtract 80h/128d; this corrects it to the true exponent, which is the number of binary digits in iX - make this the bit counter for PF BITS _2E7B_PF_BITS (also entered from PF SAVE: there is either a one-byte iX in D' with a bit counter 08, or a two-byte iX in D'E' with a bit counter 16d, or a four-byte iX in D'E'DE with a bit counter showing the actual number of significant digits): shift D'E'DE left withzero into the lo bit and the hi bit to carry; this carry represents the hi binary digit of iX - get a pointer to the tenth byte of the buffer, mem-4 byte 5; the lo digit of the print buffer - make a byte counter 05 for PF BYTES. _2E8A_PF_BYTES: get the byte at the pointer; it represents two decimal digits, see below, initially both zero - add it to itself with the carry; this doubles each of the decimal digits and adds the new binary digit to the lo decimal digit - use the DAA "decimal adjust" instruction, with which my readers are no doubt thoroughly familiar! It is used after single-byte additions, subtractions, increments or decrements when the bytes are meant to represent a pair of decimal digits. Eg if A is 37h representing 37d, and B is 84h representing 84d, ADD A,B will produce BBh in A without carry; but if the ADD A,B is followed by DAA, without disturbing the carry and half-carry flags, BBh is corrected to 21h with carry, representing 37d + 84d = 121d. So now the byte in the print buffer represents two decimal digits; originally zero, and corrected each time a new binary digit is added from iX - put this byte back at the pointer - move the pointer back to the next highest byte - decrement the byte counter and loop back to PF BYTES until it reaches zero; this adds any carry from a lower byte into the decimal digits in the higher byte - (all decimal digits adjusted for the new binary digit)loop back to PF BITS for the next binary digit - (up to nine decimal digits are now held in the five lobytes of the buffer, two to a byte) zero a byte buffer - put a source pointer on the sixth byte of the buffer, the first pair of digits, and a destination pointer on the firstbyte of the buffer - make a digit counter of nine - use RLD to drop the hi digit; which is zero, there arenever more than nine digits. The RLD instruction rotates _clockwise:
