collapseos/blk/205
Virgil Dupras 0f2d14ad8a z80a: add BREAK, instruction
This allows us to remove a lot of labels usage in boot code. This
commit has no effect on forth.bin.
2020-05-16 21:02:50 -04:00

17 lines
539 B
Plaintext

Structured flow
z80a also has words that behave similarly to IF..THEN and
BEGIN..UNTIL.
On the IF side, we have IFZ, IFNZ, IFC, IFNC, and THEN,. When
the opposite condition is met, a relative jump is made to
THEN,'s PC. For example, if you have IFZ, a jump is made when
Z is unset.
On the BEGIN,..AGAIN, side, it's a bit different. You start
with your BEGIN, instruction, and then later you issue a
JRxx, instr followed by AGAIN,. Exactly like you would do
with a label.
(cont.)