Problème langage assembleur RTL

Bonjour,
quelqu'un pourat-t-il m'expliquer ce code SVP concernant la langage RTL :

Recall that this instruction uses the bits in positions 10 and 11 in the address field to determine what comparison to perform on the AC. Depending on this bit combination, the AC is checked to see whether it is negative, equal to zero, or greater than zero. If the given condition is true, then the next instruction is skipped. This is performed by incrementing the PC register by 1.

if IR[11-10] = 00 then {if bits 10 and 11 in the IR are both 0}
If AC < 0 then PC ¬ PC+1
else If IR[11-10] = 01 then {if bit 11 = 0 and bit 10 = 1}
If AC = 0 then PC ¬ PC + 1
else If IR[11-10] = 10 then {if bit 11 = 1 and bit 10 = 0}
If AC > 0 then PC ¬ PC + 1
Merci d'avance