IF OPERATOR: "E97" EXAMPLES

Here you can see the results of full conditional operators' translation. You may need to look for some details about conditions coding and how assign operator is compiling.

1. IF x<0 THEN s := -1 ELSE s := 1; (DE - address of variable x, DC - s)

Address, code	Operations	Pascal comments
000A 01E1 000C 00DE	(DE) ==> R1	Extract x
000E 2401	compare R1 with 0	Is x < 0 ?
0010 2C0D 0012 001E	jump if >=0	Jump to ELSE branch
0014 3111 0016 011E 0018 00DC	-1 ==> R1 R1 ==> (DC)	THEN s := -1;
001A 1C0D 001C 0024	unconditional jump	ELSE bypass
001E 2111 0020 011E 0022 00DC	1 ==> R1 R1 ==> (DC)	ELSE s := 1;
0024

2. IF x<0 THEN s := -1; (DE - address of variable x, DC - s)
This short form of IF operator can be easily derived from the previous example by removal of ELSE branch and its bypass:

Address, code	Operations	Pascal comments
000A 01E1 000C 00DE	(DE) ==> R1	Extract x
000E 2401	compare R1 with 0	Is x < 0 ?
0010 2C0D 0012 001A	jump if >=0	Jump to next operator
0014 3111 0016 011E 0018 00DC	-1 ==> R1 R1 ==> (DC)	THEN s := -1;
001A

3. IF b THEN c := '0' ELSE c := '1'; (DD - address of BOOLEAN variable b, DC - c)

Address, code	Operations	Pascal comments
001C 81E1 001E 00DD	(DD)b ==> R1	Extract b (byte value)
0020 E401	compare R1b with 0b	Is b <> 0 (TRUE)?
0022 5C0D 0024 0032	jump if =0	Jump to ELSE branch if FALSE
0026 81D1 0028 0030 002A C11E 002C 00DC	30b ==> R1 R1b ==> (DC)b	THEN c := '0';
002E 1C0D 0030 003A	unconditional jump	ELSE bypass
0032 81D1 0034 0031 0036 011E 0038 00DC	31b ==> R1 R1b ==> (DC)b	ELSE c := '1';
003A