Tomasulo's algorithm: Difference between revisions

Revision as of 15:42, 17 October 2019

Revision as of 18:55, 11 May 2020

Line 85:

|Issue

|Station {{mono|r}} empty

|<sourcesyntaxhighlight lang="c">

if (RegisterStat[rs].Qi¦0) {

RS[r].Qj ← RegisterStat[rs].Qi

Line 102:

RS[r].Busy ← yes;

RegisterStat[rd].Q ← r;

</syntaxhighlight>

</source>

|-

|Load or Store

|Buffer {{mono|r}} empty

|<sourcesyntaxhighlight lang="c">

if (RegisterStat[rs].Qi¦0) {

RS[r].Qj ← RegisterStat[rs].Qi;

Line 116:

RS[r].A ← imm;

RS[r].Busy ← yes;

</syntaxhighlight>

</source>

|-

|Load only

|

|<sourcesyntaxhighlight lang="c">

RegisterStat[rt].Qi ← r;

</syntaxhighlight>

</source>

|-

|Store only

|

|<sourcesyntaxhighlight lang="c">

if (RegisterStat[rt].Qi¦0) {

RS[r].Qk ← RegisterStat[rt].Qi;

Line 134:

RS[r].Qk ← 0

};

</syntaxhighlight>

</source>

|}

Line 158:

|-

|FP operation

| <sourcesyntaxhighlight lang="text">

(RS[r].Qj = 0) and (RS[r].Qk = 0)

</syntaxhighlight>

</source>

|

Compute result: operands are in Vj and Vk

Line 166:

|Load/store step 1

|<code>RS[r].Qj = 0</code> & r is head of load-store queue

|<sourcesyntaxhighlight lang="text">

RS[r].A ← RS[r].Vj + RS[r].A;

</syntaxhighlight>

</source>

|-

|Load step 2

Line 191:

|FP operation or load

|Execution complete at {{mono|r}} & CDB available

|<sourcesyntaxhighlight lang="c">

∀x(if (RegisterStat[x].Qi = r) {

regs[x] ← result;

Line 205:

});

RS[r].Busy ← no;

</syntaxhighlight>

</source>

|-

|Store

|Execution complete at {{mono|1=r & RS[r].Qk = 0}}

|<sourcesyntaxhighlight lang="c">

Mem[RS[r].A] ← RS[r].Vk;

RS[r].Busy ← no;

</syntaxhighlight>

</source>

|}