Ok heres a rough outline , I have code on my ST which is about 300 miles away.
Basically we need to draw vertical lines which when put next to each other look like some text.
A1 points to a table of offsets from one Y to the next ,A0 points to the screen. We start D7 with 0x8000 - so that or.w d7,(a0) would plot the first pixel on the screen.
For each new line we ror.w #1 ,d7 and when the X flag gets set we know we have to move onto the next word
draw next line of pixels.
wash rinse repeat until you get to the end of the list or end of the screen
To draw a vertical line of pixels you scan through an image and for example a box ( 1,2 and 3 are the vertical lines )
line 1 would be
and the 2nd line would be
and the last line would be the same as the first
If the font is simple then you could map each vertical line in the font and call the routine ( don't recreate duplicates)
then each draw line could be jsr (xxxx.l) where you write in the address for each line or have a table and have a load of jsr(d16,an) where an is a list of the functions to draw each scan line or you could create self modifying code which creates the scan lines and you only need to know the addresses of the start of the last 320 functions