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Merge pull request #1512 from ReinUsesLisp/brk

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gl_shader_decompiler: Implement PBK and BRK
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bunnei 2018-10-23 00:01:38 -04:00 committed by GitHub
commit 848a49112a
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GPG key ID: 4AEE18F83AFDEB23
2 changed files with 43 additions and 22 deletions
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8
src/video_core/engines/shader_bytecode.h
View file

@ -1213,11 +1213,13 @@ public:
KIL,
SSY,
SYNC,
BRK,
DEPBAR,
BFE_C,
BFE_R,
BFE_IMM,
BRA,
PBK,
LD_A,
LD_C,
ST_A,
@ -1374,7 +1376,7 @@ public:
/// conditionally executed).
static bool IsPredicatedInstruction(Id opcode) {
// TODO(Subv): Add the rest of unpredicated instructions.
return opcode != Id::SSY;
return opcode != Id::SSY && opcode != Id::PBK;
}
class Matcher {
@ -1470,9 +1472,11 @@ private:
#define INST(bitstring, op, type, name) Detail::GetMatcher(bitstring, op, type, name)
INST("111000110011----", Id::KIL, Type::Flow, "KIL"),
INST("111000101001----", Id::SSY, Type::Flow, "SSY"),
INST("111000101010----", Id::PBK, Type::Flow, "PBK"),
INST("111000100100----", Id::BRA, Type::Flow, "BRA"),
INST("1111000011111---", Id::SYNC, Type::Flow, "SYNC"),
INST("111000110100---", Id::BRK, Type::Flow, "BRK"),
INST("1111000011110---", Id::DEPBAR, Type::Synch, "DEPBAR"),
INST("1111000011111---", Id::SYNC, Type::Synch, "SYNC"),
INST("1110111111011---", Id::LD_A, Type::Memory, "LD_A"),
INST("1110111110010---", Id::LD_C, Type::Memory, "LD_C"),
INST("1110111111110---", Id::ST_A, Type::Memory, "ST_A"),

55
src/video_core/renderer_opengl/gl_shader_decompiler.cpp
View file

@ -163,10 +163,11 @@ private:
const ExitMethod jmp = Scan(target, end, labels);
return exit_method = ParallelExit(no_jmp, jmp);
}
case OpCode::Id::SSY: {
// The SSY instruction uses a similar encoding as the BRA instruction.
case OpCode::Id::SSY:
case OpCode::Id::PBK: {
// The SSY and PBK use a similar encoding as the BRA instruction.
ASSERT_MSG(instr.bra.constant_buffer == 0,
"Constant buffer SSY is not supported");
"Constant buffer branching is not supported");
const u32 target = offset + instr.bra.GetBranchTarget();
labels.insert(target);
// Continue scanning for an exit method.
@ -1233,27 +1234,27 @@ private:
}
/*
* Emits code to push the input target address to the SSY address stack, incrementing the stack
* Emits code to push the input target address to the flow address stack, incrementing the stack
* top.
*/
void EmitPushToSSYStack(u32 target) {
void EmitPushToFlowStack(u32 target) {
shader.AddLine('{');
++shader.scope;
shader.AddLine("ssy_stack[ssy_stack_top] = " + std::to_string(target) + "u;");
shader.AddLine("ssy_stack_top++;");
shader.AddLine("flow_stack[flow_stack_top] = " + std::to_string(target) + "u;");
shader.AddLine("flow_stack_top++;");
--shader.scope;
shader.AddLine('}');
}
/*
* Emits code to pop an address from the SSY address stack, setting the jump address to the
* Emits code to pop an address from the flow address stack, setting the jump address to the
* popped address and decrementing the stack top.
*/
void EmitPopFromSSYStack() {
void EmitPopFromFlowStack() {
shader.AddLine('{');
++shader.scope;
shader.AddLine("ssy_stack_top--;");
shader.AddLine("jmp_to = ssy_stack[ssy_stack_top];");
shader.AddLine("flow_stack_top--;");
shader.AddLine("jmp_to = flow_stack[flow_stack_top];");
shader.AddLine("break;");
--shader.scope;
shader.AddLine('}');
@ -3265,16 +3266,32 @@ private:
// The SSY opcode tells the GPU where to re-converge divergent execution paths, it
// sets the target of the jump that the SYNC instruction will make. The SSY opcode
// has a similar structure to the BRA opcode.
ASSERT_MSG(instr.bra.constant_buffer == 0, "Constant buffer SSY is not supported");
ASSERT_MSG(instr.bra.constant_buffer == 0, "Constant buffer flow is not supported");
const u32 target = offset + instr.bra.GetBranchTarget();
EmitPushToSSYStack(target);
EmitPushToFlowStack(target);
break;
}
case OpCode::Id::PBK: {
// PBK pushes to a stack the address where BRK will jump to. This shares stack with
// SSY but using SYNC on a PBK address will kill the shader execution. We don't
// emulate this because it's very unlikely a driver will emit such invalid shader.
ASSERT_MSG(instr.bra.constant_buffer == 0, "Constant buffer PBK is not supported");
const u32 target = offset + instr.bra.GetBranchTarget();
EmitPushToFlowStack(target);
break;
}
case OpCode::Id::SYNC: {
// The SYNC opcode jumps to the address previously set by the SSY opcode
ASSERT(instr.flow.cond == Tegra::Shader::FlowCondition::Always);
EmitPopFromSSYStack();
EmitPopFromFlowStack();
break;
}
case OpCode::Id::BRK: {
// The BRK opcode jumps to the address previously set by the PBK opcode
ASSERT(instr.flow.cond == Tegra::Shader::FlowCondition::Always);
EmitPopFromFlowStack();
break;
}
case OpCode::Id::DEPBAR: {
@ -3428,11 +3445,11 @@ private:
labels.insert(subroutine.begin);
shader.AddLine("uint jmp_to = " + std::to_string(subroutine.begin) + "u;");
// TODO(Subv): Figure out the actual depth of the SSY stack, for now it seems
// unlikely that shaders will use 20 nested SSYs.
constexpr u32 SSY_STACK_SIZE = 20;
shader.AddLine("uint ssy_stack[" + std::to_string(SSY_STACK_SIZE) + "];");
shader.AddLine("uint ssy_stack_top = 0u;");
// TODO(Subv): Figure out the actual depth of the flow stack, for now it seems
// unlikely that shaders will use 20 nested SSYs and PBKs.
constexpr u32 FLOW_STACK_SIZE = 20;
shader.AddLine("uint flow_stack[" + std::to_string(FLOW_STACK_SIZE) + "];");
shader.AddLine("uint flow_stack_top = 0u;");
shader.AddLine("while (true) {");
++shader.scope;