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Added basic IRQ support

This commit is contained in:
Clifford Wolf 2015-06-25 14:08:39 +02:00
parent 982e5cc600
commit 23b700cf73
7 changed files with 546 additions and 19 deletions
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2
.gitignore vendored
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@ -1,4 +1,5 @@
/tests/*.o /tests/*.o
/firmware/start.o
/firmware/firmware.bin /firmware/firmware.bin
/firmware/firmware.elf /firmware/firmware.elf
/firmware/firmware.hex /firmware/firmware.hex
@ -16,3 +17,4 @@
/testbench.exe /testbench.exe
/testbench_axi.exe /testbench_axi.exe
/testbench.vcd /testbench.vcd
.*.swp

7
Makefile
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@ -22,12 +22,15 @@ firmware/firmware.bin: firmware/firmware.elf
riscv64-unknown-elf-objcopy -O binary $< $@ riscv64-unknown-elf-objcopy -O binary $< $@
chmod -x $@ chmod -x $@
firmware/firmware.elf: $(TEST_OBJS) firmware/sections.lds firmware/start.S firmware/sieve.c firmware/stats.c firmware/firmware.elf: $(TEST_OBJS) firmware/sections.lds firmware/start.o firmware/sieve.c firmware/stats.c
riscv64-unknown-elf-gcc -Os -m32 -march=RV32I -ffreestanding -nostdlib -o $@ \ riscv64-unknown-elf-gcc -Os -m32 -march=RV32I -ffreestanding -nostdlib -o $@ \
-Wl,-Bstatic,-T,firmware/sections.lds,-Map,firmware/firmware.map,--strip-debug \ -Wl,-Bstatic,-T,firmware/sections.lds,-Map,firmware/firmware.map,--strip-debug \
firmware/start.S firmware/sieve.c firmware/stats.c $(TEST_OBJS) -lgcc firmware/start.o firmware/sieve.c firmware/stats.c $(TEST_OBJS) -lgcc
chmod -x $@ chmod -x $@
firmware/start.o: firmware/start.S
riscv64-unknown-elf-gcc -c -m32 -o $@ $<
tests/%.o: tests/%.S tests/riscv_test.h tests/test_macros.h tests/%.o: tests/%.S tests/riscv_test.h tests/test_macros.h
riscv64-unknown-elf-gcc -m32 -march=RV32I -c -o $@ -DTEST_FUNC_NAME=$(notdir $(basename $<)) \ riscv64-unknown-elf-gcc -m32 -march=RV32I -c -o $@ -DTEST_FUNC_NAME=$(notdir $(basename $<)) \
-DTEST_FUNC_TXT='"$(notdir $(basename $<))"' -DTEST_FUNC_RET=$(notdir $(basename $<))_ret $< -DTEST_FUNC_TXT='"$(notdir $(basename $<))"' -DTEST_FUNC_RET=$(notdir $(basename $<))_ret $<

144
README.md
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@ -83,6 +83,27 @@ transaction. In the default configuration the PicoRV32 core only expects the
`mem_rdata` input to be valid in the cycle with `mem_valid && mem_ready` and `mem_rdata` input to be valid in the cycle with `mem_valid && mem_ready` and
latches the value internally. latches the value internally.
### ENABLE_EXTERNAL_IRQ (default = 0)
Set this to 1 to enable external IRQs.
### ENABLE_ILLINSTR_IRQ (default = 0)
Set this to 1 to enable the illigal instruction IRQ. This can be used for
software implementations of instructions such as `MUL` and `DIV`.
### ENABLE_TIMER_IRQ (default = 0)
Set this to 1 to enable the built-in timer and timer IRQ.
### PROGADDR_RESET (default = 0)
The start address of the program.
### PROGADDR_IRQ (default = 16)
The start address of the interrupt handler.
Performance: Performance:
------------ ------------
@ -115,10 +136,131 @@ Dhrystone benchmark results: 0.309 DMIPS/MHz (544 Dhrystones/Second/MHz)
For the Dhrystone benchmark the average CPI is 4.167. For the Dhrystone benchmark the average CPI is 4.167.
Custom Instructions:
--------------------
### IRQ Handling
The following custom instructions are supported when IRQs are enabled.
The core has 4 additional 32-bit general-purpose registers `q0 .. q3`
that are used for IRQ handling. When an IRQ triggers, the register
`q0` contains the return address and `q1` contains the IRQ number.
Registers `q2` and `q3` are uninitialized.
#### getq rd, qs
This instruction copies the value from a q-register to a general-purpose
register. The Instruction is encoded under the `custom0` opcode:
0000000 00000 000XX 000 XXXXX 0001011
f7 f5 qs f3 rd opcode
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| getq x5, q2 | custom0 5, 2, 0, 0 |
| getq x3, q0 | custom0 3, 0, 0, 0 |
| getq x1, q3 | custom0 1, 3, 0, 0 |
#### setq qd, rs
This instruction copies the value from a general-purpose register to a
q-register. The Instruction is encoded under the `custom0` opcode:
0000001 00000 XXXXX 000 000XX 0001011
f7 f5 rs f3 qd opcode
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| setq q2, x5 | custom0 2, 5, 0, 1 |
| setq q0, x3 | custom0 0, 3, 0, 1 |
| setq q3, x1 | custom0 3, 1, 0, 1 |
#### retirq
Return from interrupt. This instruction copies the value from `q0`
to the program counter and enables interrupts. The Instruction is
encoded under the `custom0` opcode:
0000010 00000 00000 000 00000 0001011
f7 f5 rs f3 rd opcode
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| retirq | custom0 0, 0, 0, 2 |
#### maskirq
Enable/disable interrupt sources. The Instruction is encoded under the
`custom0` opcode:
0000011 XXXXX 00000 000 00000 0001011
f7 f5 rs f3 rd opcode
The following interrupt sources occupy the following bits
in the `f5` field:
| Bit | Interrupt Source |
| ------| ---------------------|
| f5[0] | External IRQ |
| f5[1] | Timer Interrupt |
| f5[2] | Illegal Instruction |
| f5[3] | Reserved |
| f5[4] | Reserved |
Set bits in the IRQ mask correspond to enabled interrupt sources.
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| maskirq 0 | custom0 0, 0, 0, 3 |
| maskirq 1 | custom0 0, 0, 1, 3 |
The processor starts with all interrupts disabled.
An illegal instruction while the illegal instruction interrupt is disabled will
cause the processor to halt.
#### waitirq (unimplemented)
Pause execution until an interrupt triggers. The Instruction is encoded under the
`custom0` opcode:
0000100 00000 00000 000 00000 0001011
f7 f5 rs f3 rd opcode
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| waitirq | custom0 0, 0, 0, 4 |
#### timer
Reset the timer counter to a new value. The counter counts down cycles and
triggers the timer interrupt when transitioning from 1 to 0. Setting the
counter to zero disables the timer.
0000101 00000 XXXXX 000 00000 0001011
f7 f5 rs f3 rd opcode
Example assember code using the `custom0` mnemonic:
| Instruction | Assember Code |
| ------------------| --------------------|
| timer x2 | custom0 0, 2, 0, 5 |
Todos: Todos:
------ ------
- Optional IRQ support
- Optional FENCE support - Optional FENCE support
- Optional write-through cache - Optional write-through cache
- Optional support for compressed ISA - Optional support for compressed ISA

101
firmware/sieve.c
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@ -18,6 +18,11 @@ static bool bitmap_get(int idx)
return (bitmap[idx/32] & (1 << (idx % 32))) != 0; return (bitmap[idx/32] & (1 << (idx % 32))) != 0;
} }
static void print_chr(char ch)
{
*((volatile uint32_t*)OUTPORT) = ch;
}
static void print_str(const char *p) static void print_str(const char *p)
{ {
while (*p != 0) while (*p != 0)
@ -37,6 +42,13 @@ static void print_dec(int val)
} }
} }
static void print_hex(unsigned int val)
{
int i;
for (i = 32-4; i >= 0; i -= 4)
*((volatile uint32_t*)OUTPORT) = "0123456789ABCDEF"[(val >> i) % 16];
}
static void print_prime(int idx, int val) static void print_prime(int idx, int val)
{ {
if (idx < 10) if (idx < 10)
@ -76,3 +88,92 @@ void sieve()
} }
} }
void irq(uint32_t *regs, uint32_t irqnum)
{
static int ext_irq_count = 0;
static int timer_irq_count = 0;
if (irqnum == 0) {
ext_irq_count++;
// print_str("[EXT-IRQ]");
return;
}
if (irqnum == 1) {
timer_irq_count++;
// print_str("[TIMER-IRQ]");
return;
}
if (irqnum == 2)
{
int i, k;
uint32_t pc = regs[0] - 4;
uint32_t instr = *(uint32_t*)pc;
print_str("\n");
print_str("------------------------------------------------------------\n");
if (instr == 0x00100073) {
print_str("SBREAK instruction at 0x");
print_hex(pc);
print_str("\n");
} else {
print_str("Illegal Instruction at 0x");
print_hex(pc);
print_str(": 0x");
print_hex(instr);
print_str("\n");
}
for (i = 0; i < 8; i++)
for (k = 0; k < 4; k++)
{
int r = i + k*8;
if (r == 0) {
print_str("pc ");
} else
if (r < 10) {
print_chr('x');
print_chr('0' + r);
print_chr(' ');
print_chr(' ');
} else
if (r < 20) {
print_chr('x');
print_chr('1');
print_chr('0' + r - 10);
print_chr(' ');
} else
if (r < 30) {
print_chr('x');
print_chr('2');
print_chr('0' + r - 20);
print_chr(' ');
} else {
print_chr('x');
print_chr('3');
print_chr('0' + r - 30);
print_chr(' ');
}
print_hex(regs[r]);
print_str(k == 3 ? "\n" : " ");
}
print_str("------------------------------------------------------------\n");
print_str("Number of external IRQs counted: ");
print_dec(ext_irq_count);
print_str("\n");
print_str("Number of timer IRQs counted: ");
print_dec(timer_irq_count);
print_str("\n");
__asm__("sbreak");
return;
}
}

163
firmware/start.S
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@ -1,13 +1,174 @@
.section .text .section .text
.global start .global irq
.global sieve .global sieve
.global stats .global stats
#define TEST(n) \ #define TEST(n) \
.global n; .global n ## _ret; \ .global n; .global n ## _ret; \
addi x1, zero, 1000; \
custom0 0,1,0,5; /* timer x1 */ \
jal zero,n; n ## _ret: jal zero,n; n ## _ret:
reset_vec:
custom0 0,0,7,3 // maskirq 7
j start
nop
nop
irq_vec:
/* save registers */
custom0 2,1,0,1 // setq q2, x1
custom0 3,2,0,1 // setq q3, x2
lui x1, %hi(irq_regs)
addi x1, x1, %lo(irq_regs)
custom0 2,0,0,0 // getq x2, q0
sw x2, 0*4(x1)
custom0 2,2,0,0 // getq x2, q2
sw x2, 1*4(x1)
custom0 2,3,0,0 // getq x2, q3
sw x2, 2*4(x1)
sw x3, 3*4(x1)
sw x4, 4*4(x1)
sw x5, 5*4(x1)
sw x6, 6*4(x1)
sw x7, 7*4(x1)
sw x8, 8*4(x1)
sw x9, 9*4(x1)
sw x10, 10*4(x1)
sw x11, 11*4(x1)
sw x12, 12*4(x1)
sw x13, 13*4(x1)
sw x14, 14*4(x1)
sw x15, 15*4(x1)
sw x16, 16*4(x1)
sw x17, 17*4(x1)
sw x18, 18*4(x1)
sw x19, 19*4(x1)
sw x20, 20*4(x1)
sw x21, 21*4(x1)
sw x22, 22*4(x1)
sw x23, 23*4(x1)
sw x24, 24*4(x1)
sw x25, 25*4(x1)
sw x26, 26*4(x1)
sw x27, 27*4(x1)
sw x28, 28*4(x1)
sw x29, 29*4(x1)
sw x30, 30*4(x1)
sw x31, 31*4(x1)
/* call interrupt handler */
lui sp, %hi(irq_stack_top)
addi sp, sp, %lo(irq_stack_top)
// arg0 = address of regs
lui a0, %hi(irq_regs)
addi a0, a0, %lo(irq_regs)
// arg1 = interrupt type
custom0 11,1,0,0 // getq x11, q1
// call to c function
jal ra, irq
/* restore registers */
lui x1, %hi(irq_regs)
addi x1, x1, %lo(irq_regs)
lw x2, 0*4(x1)
custom0 0,2,0,1 // setq q0, x2
lw x2, 1*4(x1)
custom0 1,2,0,1 // setq q1, x2
lw x2, 2*4(x1)
custom0 2,2,0,1 // setq q2, x2
lw x3, 3*4(x1)
lw x4, 4*4(x1)
lw x5, 5*4(x1)
lw x6, 6*4(x1)
lw x7, 7*4(x1)
lw x8, 8*4(x1)
lw x9, 9*4(x1)
lw x10, 10*4(x1)
lw x11, 11*4(x1)
lw x12, 12*4(x1)
lw x13, 13*4(x1)
lw x14, 14*4(x1)
lw x15, 15*4(x1)
lw x16, 16*4(x1)
lw x17, 17*4(x1)
lw x18, 18*4(x1)
lw x19, 19*4(x1)
lw x20, 20*4(x1)
lw x21, 21*4(x1)
lw x22, 22*4(x1)
lw x23, 23*4(x1)
lw x24, 24*4(x1)
lw x25, 25*4(x1)
lw x26, 26*4(x1)
lw x27, 27*4(x1)
lw x28, 28*4(x1)
lw x29, 29*4(x1)
lw x30, 30*4(x1)
lw x31, 31*4(x1)
custom0 1,1,0,0 // getq x1, q1
custom0 2,2,0,0 // getq x2, q2
custom0 0,0,0,2 // retirq
irq_regs:
// registers are saved to this memory region
// the program counter is saved as register 0
.fill 32,4
irq_stack:
.fill 128,4
irq_stack_top:
start: start:
addi x1, zero, 0
addi x2, zero, 0
addi x3, zero, 0
addi x4, zero, 0
addi x5, zero, 0
addi x6, zero, 0
addi x7, zero, 0
addi x8, zero, 0
addi x9, zero, 0
addi x10, zero, 0
addi x11, zero, 0
addi x12, zero, 0
addi x13, zero, 0
addi x14, zero, 0
addi x15, zero, 0
addi x16, zero, 0
addi x17, zero, 0
addi x18, zero, 0
addi x19, zero, 0
addi x20, zero, 0
addi x21, zero, 0
addi x22, zero, 0
addi x23, zero, 0
addi x24, zero, 0
addi x25, zero, 0
addi x26, zero, 0
addi x27, zero, 0
addi x28, zero, 0
addi x29, zero, 0
addi x30, zero, 0
addi x31, zero, 0
TEST(lui) TEST(lui)
TEST(auipc) TEST(auipc)
TEST(j) TEST(j)

134
picorv32.v
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@ -29,9 +29,14 @@ module picorv32 #(
parameter ENABLE_COUNTERS = 1, parameter ENABLE_COUNTERS = 1,
parameter ENABLE_REGS_16_31 = 1, parameter ENABLE_REGS_16_31 = 1,
parameter ENABLE_REGS_DUALPORT = 1, parameter ENABLE_REGS_DUALPORT = 1,
parameter LATCHED_MEM_RDATA = 0 parameter LATCHED_MEM_RDATA = 0,
parameter ENABLE_EXTERNAL_IRQ = 0,
parameter ENABLE_ILLINSTR_IRQ = 0,
parameter ENABLE_TIMER_IRQ = 0,
parameter PROGADDR_RESET = 0,
parameter PROGADDR_IRQ = 16
) ( ) (
input clk, resetn, input clk, resetn, irq,
output reg trap, output reg trap,
output reg mem_valid, output reg mem_valid,
@ -50,8 +55,11 @@ module picorv32 #(
output reg [31:0] mem_la_wdata, output reg [31:0] mem_la_wdata,
output reg [ 3:0] mem_la_wstrb output reg [ 3:0] mem_la_wstrb
); );
localparam integer regfile_size = ENABLE_REGS_16_31 ? 32 : 16; localparam ENABLE_IRQ = ENABLE_EXTERNAL_IRQ || ENABLE_ILLINSTR_IRQ || ENABLE_TIMER_IRQ;
localparam integer regindex_bits = ENABLE_REGS_16_31 ? 5 : 4;
localparam integer irqregs_offset = ENABLE_REGS_16_31 ? 32 : 16;
localparam integer regfile_size = (ENABLE_REGS_16_31 ? 32 : 16) + 4*ENABLE_IRQ;
localparam integer regindex_bits = (ENABLE_REGS_16_31 ? 5 : 4) + ENABLE_IRQ;
reg [63:0] count_cycle, count_instr; reg [63:0] count_cycle, count_instr;
reg [31:0] reg_pc, reg_next_pc, reg_op1, reg_op2, reg_out, reg_alu_out; reg [31:0] reg_pc, reg_next_pc, reg_op1, reg_op2, reg_out, reg_alu_out;
@ -60,6 +68,11 @@ module picorv32 #(
wire [31:0] next_pc; wire [31:0] next_pc;
reg irq_active;
reg [4:0] irq_mask;
reg [4:0] irq_pending;
reg [31:0] timer;
// Memory Interface // Memory Interface
reg [1:0] mem_state; reg [1:0] mem_state;
@ -166,6 +179,7 @@ module picorv32 #(
reg instr_addi, instr_slti, instr_sltiu, instr_xori, instr_ori, instr_andi, instr_slli, instr_srli, instr_srai; reg instr_addi, instr_slti, instr_sltiu, instr_xori, instr_ori, instr_andi, instr_slli, instr_srli, instr_srai;
reg instr_add, instr_sub, instr_sll, instr_slt, instr_sltu, instr_xor, instr_srl, instr_sra, instr_or, instr_and; reg instr_add, instr_sub, instr_sll, instr_slt, instr_sltu, instr_xor, instr_srl, instr_sra, instr_or, instr_and;
reg instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh; reg instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh;
reg instr_getq, instr_setq, instr_retirq, instr_maskirq, instr_waitirq, instr_timer;
wire instr_trap; wire instr_trap;
reg [regindex_bits-1:0] decoded_rd, decoded_rs1, decoded_rs2; reg [regindex_bits-1:0] decoded_rd, decoded_rs1, decoded_rs2;
@ -193,7 +207,8 @@ module picorv32 #(
instr_lb, instr_lh, instr_lw, instr_lbu, instr_lhu, instr_sb, instr_sh, instr_sw, instr_lb, instr_lh, instr_lw, instr_lbu, instr_lhu, instr_sb, instr_sh, instr_sw,
instr_addi, instr_slti, instr_sltiu, instr_xori, instr_ori, instr_andi, instr_slli, instr_srli, instr_srai, instr_addi, instr_slti, instr_sltiu, instr_xori, instr_ori, instr_andi, instr_slli, instr_srli, instr_srai,
instr_add, instr_sub, instr_sll, instr_slt, instr_sltu, instr_xor, instr_srl, instr_sra, instr_or, instr_and, instr_add, instr_sub, instr_sll, instr_slt, instr_sltu, instr_xor, instr_srl, instr_sra, instr_or, instr_and,
instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh}; instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh,
instr_getq, instr_setq, instr_retirq, instr_maskirq, instr_waitirq, instr_timer};
wire is_rdcycle_rdcycleh_rdinstr_rdinstrh; wire is_rdcycle_rdcycleh_rdinstr_rdinstrh;
assign is_rdcycle_rdcycleh_rdinstr_rdinstrh = |{instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh}; assign is_rdcycle_rdcycleh_rdinstr_rdinstrh = |{instr_rdcycle, instr_rdcycleh, instr_rdinstr, instr_rdinstrh};
@ -250,6 +265,13 @@ module picorv32 #(
if (instr_rdinstr) new_instruction = "rdinstr"; if (instr_rdinstr) new_instruction = "rdinstr";
if (instr_rdinstrh) new_instruction = "rdinstrh"; if (instr_rdinstrh) new_instruction = "rdinstrh";
if (instr_getq) new_instruction = "getq";
if (instr_setq) new_instruction = "setq";
if (instr_retirq) new_instruction = "retirq";
if (instr_maskirq) new_instruction = "maskirq";
if (instr_waitirq) new_instruction = "waitirq";
if (instr_timer) new_instruction = "timer";
if (new_instruction) if (new_instruction)
instruction = new_instruction; instruction = new_instruction;
end end
@ -268,6 +290,7 @@ module picorv32 #(
instr_jal <= mem_rdata_latched[6:0] == 7'b1101111; instr_jal <= mem_rdata_latched[6:0] == 7'b1101111;
instr_jalr <= mem_rdata_latched[6:0] == 7'b1100111; instr_jalr <= mem_rdata_latched[6:0] == 7'b1100111;
instr_retirq <= mem_rdata_latched[6:0] == 7'b0001011 && mem_rdata_latched[31:25] == 7'b0000010 && ENABLE_IRQ;
is_beq_bne_blt_bge_bltu_bgeu <= mem_rdata_latched[6:0] == 7'b1100011; is_beq_bne_blt_bge_bltu_bgeu <= mem_rdata_latched[6:0] == 7'b1100011;
is_lb_lh_lw_lbu_lhu <= mem_rdata_latched[6:0] == 7'b0000011; is_lb_lh_lw_lbu_lhu <= mem_rdata_latched[6:0] == 7'b0000011;
@ -280,6 +303,12 @@ module picorv32 #(
decoded_rd <= mem_rdata_latched[11:7]; decoded_rd <= mem_rdata_latched[11:7];
decoded_rs1 <= mem_rdata_latched[19:15]; decoded_rs1 <= mem_rdata_latched[19:15];
decoded_rs2 <= mem_rdata_latched[24:20]; decoded_rs2 <= mem_rdata_latched[24:20];
if (mem_rdata_latched[6:0] == 7'b0001011 && mem_rdata_latched[31:25] == 7'b0000000 && ENABLE_IRQ)
decoded_rs1[regindex_bits-1] <= 1; // instr_getq
if (mem_rdata_latched[6:0] == 7'b0001011 && mem_rdata_latched[31:25] == 7'b0000010 && ENABLE_IRQ)
decoded_rs1 <= irqregs_offset; // instr_retirq
end end
if (decoder_trigger && !decoder_pseudo_trigger) begin if (decoder_trigger && !decoder_pseudo_trigger) begin
@ -329,6 +358,12 @@ module picorv32 #(
instr_rdinstr <= (mem_rdata_q[6:0] == 7'b1110011 && mem_rdata_q[31:12] == 'b11000000001000000010) && ENABLE_COUNTERS; instr_rdinstr <= (mem_rdata_q[6:0] == 7'b1110011 && mem_rdata_q[31:12] == 'b11000000001000000010) && ENABLE_COUNTERS;
instr_rdinstrh <= (mem_rdata_q[6:0] == 7'b1110011 && mem_rdata_q[31:12] == 'b11001000001000000010) && ENABLE_COUNTERS; instr_rdinstrh <= (mem_rdata_q[6:0] == 7'b1110011 && mem_rdata_q[31:12] == 'b11001000001000000010) && ENABLE_COUNTERS;
instr_getq <= mem_rdata_q[6:0] == 7'b0001011 && mem_rdata_q[31:25] == 7'b0000000 && ENABLE_IRQ;
instr_setq <= mem_rdata_q[6:0] == 7'b0001011 && mem_rdata_q[31:25] == 7'b0000001 && ENABLE_IRQ;
instr_maskirq <= mem_rdata_q[6:0] == 7'b0001011 && mem_rdata_q[31:25] == 7'b0000011 && ENABLE_IRQ;
instr_waitirq <= mem_rdata_q[6:0] == 7'b0001011 && mem_rdata_q[31:25] == 7'b0000100 && ENABLE_IRQ;
instr_timer <= mem_rdata_q[6:0] == 7'b0001011 && mem_rdata_q[31:25] == 7'b0000101 && ENABLE_TIMER_IRQ;
is_slli_srli_srai <= is_alu_reg_imm && |{ is_slli_srli_srai <= is_alu_reg_imm && |{
mem_rdata_q[14:12] == 3'b001 && mem_rdata_q[31:25] == 7'b0000000, mem_rdata_q[14:12] == 3'b001 && mem_rdata_q[31:25] == 7'b0000000,
mem_rdata_q[14:12] == 3'b101 && mem_rdata_q[31:25] == 7'b0000000, mem_rdata_q[14:12] == 3'b101 && mem_rdata_q[31:25] == 7'b0000000,
@ -380,6 +415,7 @@ module picorv32 #(
localparam cpu_state_stmem = 6; localparam cpu_state_stmem = 6;
localparam cpu_state_ldmem = 7; localparam cpu_state_ldmem = 7;
reg [2:0] cpu_state; reg [2:0] cpu_state;
reg [1:0] irq_state;
reg set_mem_do_rinst; reg set_mem_do_rinst;
reg set_mem_do_rdata; reg set_mem_do_rdata;
@ -448,12 +484,22 @@ module picorv32 #(
if (ENABLE_COUNTERS) if (ENABLE_COUNTERS)
count_cycle <= resetn ? count_cycle + 1 : 0; count_cycle <= resetn ? count_cycle + 1 : 0;
if (ENABLE_TIMER_IRQ && timer) begin
if (timer - 1 == 0)
irq_pending[1] <= 1;
timer <= timer - 1;
end
if (ENABLE_EXTERNAL_IRQ && irq) begin
irq_pending[0] <= 1;
end
decoder_trigger <= mem_do_rinst && mem_done; decoder_trigger <= mem_do_rinst && mem_done;
decoder_pseudo_trigger <= 0; decoder_pseudo_trigger <= 0;
if (!resetn) begin if (!resetn) begin
reg_pc <= 0; reg_pc <= PROGADDR_RESET;
reg_next_pc <= 0; reg_next_pc <= PROGADDR_RESET;
if (ENABLE_COUNTERS) if (ENABLE_COUNTERS)
count_instr <= 0; count_instr <= 0;
latched_store <= 0; latched_store <= 0;
@ -462,6 +508,11 @@ module picorv32 #(
latched_is_lu <= 0; latched_is_lu <= 0;
latched_is_lh <= 0; latched_is_lh <= 0;
latched_is_lb <= 0; latched_is_lb <= 0;
irq_active <= 0;
irq_mask <= 0;
irq_pending <= 0;
irq_state <= 0;
timer <= 0;
cpu_state <= cpu_state_fetch; cpu_state <= cpu_state_fetch;
end else end else
(* parallel_case, full_case *) (* parallel_case, full_case *)
@ -487,6 +538,24 @@ module picorv32 #(
$display("ST_RD: %2d 0x%08x", latched_rd, latched_stalu ? reg_alu_out : reg_out); $display("ST_RD: %2d 0x%08x", latched_rd, latched_stalu ? reg_alu_out : reg_out);
`endif `endif
cpuregs[latched_rd] <= latched_stalu ? reg_alu_out : reg_out; cpuregs[latched_rd] <= latched_stalu ? reg_alu_out : reg_out;
end else
if (ENABLE_IRQ && irq_state[0]) begin
cpuregs[latched_rd] <= current_pc;
current_pc = PROGADDR_IRQ;
irq_active <= 1;
mem_do_rinst <= 1;
end else
if (ENABLE_IRQ && irq_state[1]) begin
cpuregs[latched_rd] <=
irq_pending[0] && irq_mask[0] ? 0 :
irq_pending[1] && irq_mask[1] ? 1 :
irq_pending[2] && irq_mask[2] ? 2 :
irq_pending[3] && irq_mask[3] ? 3 : 4;
irq_pending <=
irq_pending[0] && irq_mask[0] ? irq_pending & 5'b11110 :
irq_pending[1] && irq_mask[1] ? irq_pending & 5'b11101 :
irq_pending[2] && irq_mask[2] ? irq_pending & 5'b11011 :
irq_pending[3] && irq_mask[3] ? irq_pending & 5'b10111 : irq_pending & 5'b01111;
end end
reg_pc <= current_pc; reg_pc <= current_pc;
@ -500,6 +569,12 @@ module picorv32 #(
latched_is_lb <= 0; latched_is_lb <= 0;
latched_rd <= decoded_rd; latched_rd <= decoded_rd;
if (ENABLE_IRQ && ((decoder_trigger && !irq_active && |(irq_pending & irq_mask)) || irq_state)) begin
irq_state <=
irq_state == 2'b00 ? 2'b01 :
irq_state == 2'b01 ? 2'b10 : 2'b00;
latched_rd <= irqregs_offset | irq_state[0];
end else
if (decoder_trigger) begin if (decoder_trigger) begin
`ifdef DEBUG `ifdef DEBUG
$display("-- %-0t", $time); $display("-- %-0t", $time);
@ -516,7 +591,7 @@ module picorv32 #(
latched_branch <= 1; latched_branch <= 1;
end else begin end else begin
mem_do_rinst <= 0; mem_do_rinst <= 0;
mem_do_prefetch <= !instr_jalr; mem_do_prefetch <= !instr_jalr && !instr_retirq;
cpu_state <= cpu_state_ld_rs1; cpu_state <= cpu_state_ld_rs1;
end end
end end
@ -531,6 +606,10 @@ module picorv32 #(
`ifdef DEBUG `ifdef DEBUG
$display("SBREAK OR UNSUPPORTED INSN AT 0x%08x", reg_pc); $display("SBREAK OR UNSUPPORTED INSN AT 0x%08x", reg_pc);
`endif `endif
if (ENABLE_ILLINSTR_IRQ && irq_mask[2] && !irq_active) begin
irq_pending[2] <= 1;
cpu_state <= cpu_state_fetch;
end else
cpu_state <= cpu_state_trap; cpu_state <= cpu_state_trap;
end else end else
if (is_rdcycle_rdcycleh_rdinstr_rdinstrh) begin if (is_rdcycle_rdcycleh_rdinstr_rdinstrh) begin
@ -553,6 +632,32 @@ module picorv32 #(
reg_op2 <= decoded_imm; reg_op2 <= decoded_imm;
mem_do_rinst <= mem_do_prefetch; mem_do_rinst <= mem_do_prefetch;
cpu_state <= cpu_state_exec; cpu_state <= cpu_state_exec;
end else
if (ENABLE_IRQ && instr_getq) begin
reg_out <= cpuregs[decoded_rs1];
latched_store <= 1;
cpu_state <= cpu_state_fetch;
end else
if (ENABLE_IRQ && instr_setq) begin
reg_out <= cpuregs[decoded_rs1];
latched_rd <= latched_rd | irqregs_offset;
latched_store <= 1;
cpu_state <= cpu_state_fetch;
end else
if (ENABLE_IRQ && instr_retirq) begin
irq_active <= 0;
latched_branch <= 1;
latched_store <= 1;
reg_out <= cpuregs[decoded_rs1];
cpu_state <= cpu_state_fetch;
end else
if (ENABLE_IRQ && instr_maskirq) begin
irq_mask = decoded_rs2;
cpu_state <= cpu_state_fetch;
end else
if (ENABLE_TIMER_IRQ && instr_timer) begin
timer <= cpuregs[decoded_rs1];
cpu_state <= cpu_state_fetch;
end else begin end else begin
`ifdef DEBUG `ifdef DEBUG
$display("LD_RS1: %2d 0x%08x", decoded_rs1, decoded_rs1 ? cpuregs[decoded_rs1] : 0); $display("LD_RS1: %2d 0x%08x", decoded_rs1, decoded_rs1 ? cpuregs[decoded_rs1] : 0);
@ -745,9 +850,12 @@ endmodule
module picorv32_axi #( module picorv32_axi #(
parameter ENABLE_COUNTERS = 1, parameter ENABLE_COUNTERS = 1,
parameter ENABLE_REGS_16_31 = 1, parameter ENABLE_REGS_16_31 = 1,
parameter ENABLE_REGS_DUALPORT = 1 parameter ENABLE_REGS_DUALPORT = 1,
parameter ENABLE_EXTERNAL_IRQ = 0,
parameter ENABLE_ILLINSTR_IRQ = 0,
parameter ENABLE_TIMER_IRQ = 0
) ( ) (
input clk, resetn, input clk, resetn, irq,
output trap, output trap,
// AXI4-lite master memory interface // AXI4-lite master memory interface
@ -814,10 +922,14 @@ module picorv32_axi #(
picorv32 #( picorv32 #(
.ENABLE_COUNTERS (ENABLE_COUNTERS ), .ENABLE_COUNTERS (ENABLE_COUNTERS ),
.ENABLE_REGS_16_31 (ENABLE_REGS_16_31 ), .ENABLE_REGS_16_31 (ENABLE_REGS_16_31 ),
.ENABLE_REGS_DUALPORT(ENABLE_REGS_DUALPORT) .ENABLE_REGS_DUALPORT(ENABLE_REGS_DUALPORT),
.ENABLE_EXTERNAL_IRQ (ENABLE_EXTERNAL_IRQ ),
.ENABLE_ILLINSTR_IRQ (ENABLE_ILLINSTR_IRQ ),
.ENABLE_TIMER_IRQ (ENABLE_TIMER_IRQ )
) picorv32_core ( ) picorv32_core (
.clk (clk ), .clk (clk ),
.resetn (resetn ), .resetn (resetn ),
.irq (irq ),
.trap (trap ), .trap (trap ),
.mem_valid(mem_valid), .mem_valid(mem_valid),
.mem_addr (mem_addr ), .mem_addr (mem_addr ),

8
testbench.v
View File

@ -6,6 +6,7 @@ module testbench;
reg clk = 1; reg clk = 1;
reg resetn = 0; reg resetn = 0;
wire irq = &uut.picorv32_core.count_cycle[12:0];
wire trap; wire trap;
always #5 clk = ~clk; always #5 clk = ~clk;
@ -37,9 +38,14 @@ module testbench;
wire mem_axi_rready; wire mem_axi_rready;
reg [31:0] mem_axi_rdata; reg [31:0] mem_axi_rdata;
picorv32_axi uut ( picorv32_axi #(
.ENABLE_EXTERNAL_IRQ (1),
.ENABLE_ILLINSTR_IRQ (1),
.ENABLE_TIMER_IRQ (1)
) uut (
.clk (clk ), .clk (clk ),
.resetn (resetn ), .resetn (resetn ),
.irq (irq ),
.trap (trap ), .trap (trap ),
.mem_axi_awvalid(mem_axi_awvalid), .mem_axi_awvalid(mem_axi_awvalid),
.mem_axi_awready(mem_axi_awready), .mem_axi_awready(mem_axi_awready),