TDL relative hex loader record format
from TDL Z80 ZPU manual and relocating loader program
for ZAP monitor V2.0 Jan 1977 and Loader V3.2 Dec 1976.
Herb Johnson Oct 2012

Intel/TDL hex record format

first char is ';' for relative format or ':' for Intel absolute hex format
rest of record is hex byte values as pair of ASCII hex chars 0-9 and A-F capitals.
first byte is record length as in Intel format address bytes + data bytes + checksum
second/third byte is 16 bit address high/low byte
4th byte is 01 for data format record, I think 00 is a jump-to-address record
remaining bytes is data except last byte
last byte is checksum of all previous bytes, modulo 256 compliment (zero sum)
LF or CRLF ends record.

Absolute or Intel data format: all data bytes are memory content from start of
record address.

TDL Relative record format, as interpreted by Herb Johnson, from loader program.

Relative loader saves in BC' register, the relative page (high byte in B) offset
as read from front-panel data switches. This 16 bit value is saved in HL and IX
registers. IX is used as index plus record address, to load into memory. E is 
used to count down bytes to read and load from record. When zero, the last 
byte is read as checksum.

Relative record data format is
first byte is bit pattern for next eight bytes
2nd-9th bytes in record are data. 
10th byte is bit pattern for next eight bytes
11th-18th bytes in record are data. 
...and so on until the last data byte, followed by checksum byte. 
The bit pattern does not carry over to the next record.

The bit pattern byte is left-shifted into carry,
before the data byte is read. If carry is set for a data byte, then that byte
and the next must be a low/high byte address. The second data byte is read,
the relocation value is added to the low/high byte pair, and the 
low/high bytes are stored as a relocated address. Otherwise, bytes are
stored without "relocation".

Therefore, the bit pattern byte indicates the relative location (to the bit 
pattern byte) of the low byte of a low/high address byte pair in the record. 

Here's an example of a pair of relative format records and the resulting code,
 from the 1K ZAP monitor V2.0 and a recovered paper tape image of that same monitor.

;1800000149C30803C37403C37D2403C32202C33302C3902202C3820292
;18001501093E00C9C31700C3FF2002CD1303F90E2ACD80220218150D45 

;first record
49		;relocation, 01001001, shift LEFT to read each bit
C30803	JMP 0308		;relocate address
C37403	JMP 0374		;relocate address
C37D		
24		;relocation, 00100100
03		JMP 037D
C32202	JMP 0222
C33302	JMP 0233
C3
90		;relocation, 10010000
2202		JMP 0222
C38202	JMP 0282
;second record
09		;relocation, 00001001
3E 00		MVI A,00H
C9		RET
C31700	JMP 0017		;relocate address
C3FF		
20		;relocation, 00100000
02		JMP 02FF	;relocate address
CD1303	CALL 0313
F9		SPHL
0E2A		MVI C,2AH
CD
80		;reloation, 10000000
2202		CALL 0222
1815		JMPR 15H
0D		DB CR
;next record.....

Herb Johnson