aboutsummaryrefslogtreecommitdiff
path: root/hw
diff options
context:
space:
mode:
Diffstat (limited to 'hw')
-rw-r--r--hw/milkymist-pfpu.c536
1 files changed, 536 insertions, 0 deletions
diff --git a/hw/milkymist-pfpu.c b/hw/milkymist-pfpu.c
new file mode 100644
index 0000000000..4831e00b81
--- /dev/null
+++ b/hw/milkymist-pfpu.c
@@ -0,0 +1,536 @@
+/*
+ * QEMU model of the Milkymist programmable FPU.
+ *
+ * Copyright (c) 2010 Michael Walle <michael@walle.cc>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Specification available at:
+ * http://www.milkymist.org/socdoc/pfpu.pdf
+ *
+ */
+
+#include "hw.h"
+#include "sysbus.h"
+#include "trace.h"
+#include "qemu-log.h"
+#include "qemu-error.h"
+#include <math.h>
+
+/* #define TRACE_EXEC */
+
+#ifdef TRACE_EXEC
+# define D_EXEC(x) x
+#else
+# define D_EXEC(x)
+#endif
+
+enum {
+ R_CTL = 0,
+ R_MESHBASE,
+ R_HMESHLAST,
+ R_VMESHLAST,
+ R_CODEPAGE,
+ R_VERTICES,
+ R_COLLISIONS,
+ R_STRAYWRITES,
+ R_LASTDMA,
+ R_PC,
+ R_DREGBASE,
+ R_CODEBASE,
+ R_MAX
+};
+
+enum {
+ CTL_START_BUSY = (1<<0),
+};
+
+enum {
+ OP_NOP = 0,
+ OP_FADD,
+ OP_FSUB,
+ OP_FMUL,
+ OP_FABS,
+ OP_F2I,
+ OP_I2F,
+ OP_VECTOUT,
+ OP_SIN,
+ OP_COS,
+ OP_ABOVE,
+ OP_EQUAL,
+ OP_COPY,
+ OP_IF,
+ OP_TSIGN,
+ OP_QUAKE,
+};
+
+enum {
+ GPR_X = 0,
+ GPR_Y = 1,
+ GPR_FLAGS = 2,
+};
+
+enum {
+ LATENCY_FADD = 5,
+ LATENCY_FSUB = 5,
+ LATENCY_FMUL = 7,
+ LATENCY_FABS = 2,
+ LATENCY_F2I = 2,
+ LATENCY_I2F = 3,
+ LATENCY_VECTOUT = 0,
+ LATENCY_SIN = 4,
+ LATENCY_COS = 4,
+ LATENCY_ABOVE = 2,
+ LATENCY_EQUAL = 2,
+ LATENCY_COPY = 2,
+ LATENCY_IF = 2,
+ LATENCY_TSIGN = 2,
+ LATENCY_QUAKE = 2,
+ MAX_LATENCY = 7
+};
+
+#define GPR_BEGIN 0x100
+#define GPR_END 0x17f
+#define MICROCODE_BEGIN 0x200
+#define MICROCODE_END 0x3ff
+#define MICROCODE_WORDS 2048
+
+#define REINTERPRET_CAST(type, val) (*((type *)&(val)))
+
+#ifdef TRACE_EXEC
+static const char *opcode_to_str[] = {
+ "NOP", "FADD", "FSUB", "FMUL", "FABS", "F2I", "I2F", "VECTOUT",
+ "SIN", "COS", "ABOVE", "EQUAL", "COPY", "IF", "TSIGN", "QUAKE",
+};
+#endif
+
+struct MilkymistPFPUState {
+ SysBusDevice busdev;
+ CharDriverState *chr;
+ qemu_irq irq;
+
+ uint32_t regs[R_MAX];
+ uint32_t gp_regs[128];
+ uint32_t microcode[MICROCODE_WORDS];
+
+ int output_queue_pos;
+ uint32_t output_queue[MAX_LATENCY];
+};
+typedef struct MilkymistPFPUState MilkymistPFPUState;
+
+static inline target_phys_addr_t
+get_dma_address(uint32_t base, uint32_t x, uint32_t y)
+{
+ return base + 8 * (128 * y + x);
+}
+
+static inline void
+output_queue_insert(MilkymistPFPUState *s, uint32_t val, int pos)
+{
+ s->output_queue[(s->output_queue_pos + pos) % MAX_LATENCY] = val;
+}
+
+static inline uint32_t
+output_queue_remove(MilkymistPFPUState *s)
+{
+ return s->output_queue[s->output_queue_pos];
+}
+
+static inline void
+output_queue_advance(MilkymistPFPUState *s)
+{
+ s->output_queue[s->output_queue_pos] = 0;
+ s->output_queue_pos = (s->output_queue_pos + 1) % MAX_LATENCY;
+}
+
+static int pfpu_decode_insn(MilkymistPFPUState *s)
+{
+ uint32_t pc = s->regs[R_PC];
+ uint32_t insn = s->microcode[pc];
+ uint32_t reg_a = (insn >> 18) & 0x7f;
+ uint32_t reg_b = (insn >> 11) & 0x7f;
+ uint32_t op = (insn >> 7) & 0xf;
+ uint32_t reg_d = insn & 0x7f;
+ uint32_t r;
+ int latency = 0;
+
+ switch (op) {
+ case OP_NOP:
+ break;
+ case OP_FADD:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = a + b;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_FADD;
+ D_EXEC(qemu_log("ADD a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_FSUB:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = a - b;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_FSUB;
+ D_EXEC(qemu_log("SUB a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_FMUL:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = a * b;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_FMUL;
+ D_EXEC(qemu_log("MUL a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_FABS:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float t = fabsf(a);
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_FABS;
+ D_EXEC(qemu_log("ABS a=%f t=%f, r=%08x\n", a, t, r));
+ } break;
+ case OP_F2I:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ int32_t t = a;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_F2I;
+ D_EXEC(qemu_log("F2I a=%f t=%d, r=%08x\n", a, t, r));
+ } break;
+ case OP_I2F:
+ {
+ int32_t a = REINTERPRET_CAST(int32_t, s->gp_regs[reg_a]);
+ float t = a;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_I2F;
+ D_EXEC(qemu_log("I2F a=%08x t=%f, r=%08x\n", a, t, r));
+ } break;
+ case OP_VECTOUT:
+ {
+ uint32_t a = cpu_to_be32(s->gp_regs[reg_a]);
+ uint32_t b = cpu_to_be32(s->gp_regs[reg_b]);
+ target_phys_addr_t dma_ptr =
+ get_dma_address(s->regs[R_MESHBASE],
+ s->gp_regs[GPR_X], s->gp_regs[GPR_Y]);
+ cpu_physical_memory_write(dma_ptr, (uint8_t *)&a, 4);
+ cpu_physical_memory_write(dma_ptr + 4, (uint8_t *)&b, 4);
+ s->regs[R_LASTDMA] = dma_ptr + 4;
+ D_EXEC(qemu_log("VECTOUT a=%08x b=%08x dma=%08x\n", a, b, dma_ptr));
+ trace_milkymist_pfpu_vectout(a, b, dma_ptr);
+ } break;
+ case OP_SIN:
+ {
+ int32_t a = REINTERPRET_CAST(int32_t, s->gp_regs[reg_a]);
+ float t = sinf(a * (1.0f / (M_PI * 4096.0f)));
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_SIN;
+ D_EXEC(qemu_log("SIN a=%d t=%f, r=%08x\n", a, t, r));
+ } break;
+ case OP_COS:
+ {
+ int32_t a = REINTERPRET_CAST(int32_t, s->gp_regs[reg_a]);
+ float t = cosf(a * (1.0f / (M_PI * 4096.0f)));
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_COS;
+ D_EXEC(qemu_log("COS a=%d t=%f, r=%08x\n", a, t, r));
+ } break;
+ case OP_ABOVE:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = (a > b) ? 1.0f : 0.0f;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_ABOVE;
+ D_EXEC(qemu_log("ABOVE a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_EQUAL:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = (a == b) ? 1.0f : 0.0f;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_EQUAL;
+ D_EXEC(qemu_log("EQUAL a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_COPY:
+ {
+ r = s->gp_regs[reg_a];
+ latency = LATENCY_COPY;
+ D_EXEC(qemu_log("COPY"));
+ } break;
+ case OP_IF:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ uint32_t f = s->gp_regs[GPR_FLAGS];
+ float t = (f != 0) ? a : b;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_IF;
+ D_EXEC(qemu_log("IF f=%u a=%f b=%f t=%f, r=%08x\n", f, a, b, t, r));
+ } break;
+ case OP_TSIGN:
+ {
+ float a = REINTERPRET_CAST(float, s->gp_regs[reg_a]);
+ float b = REINTERPRET_CAST(float, s->gp_regs[reg_b]);
+ float t = (b < 0) ? -a : a;
+ r = REINTERPRET_CAST(uint32_t, t);
+ latency = LATENCY_TSIGN;
+ D_EXEC(qemu_log("TSIGN a=%f b=%f t=%f, r=%08x\n", a, b, t, r));
+ } break;
+ case OP_QUAKE:
+ {
+ uint32_t a = s->gp_regs[reg_a];
+ r = 0x5f3759df - (a >> 1);
+ latency = LATENCY_QUAKE;
+ D_EXEC(qemu_log("QUAKE a=%d r=%08x\n", a, r));
+ } break;
+
+ default:
+ error_report("milkymist_pfpu: unknown opcode %d\n", op);
+ break;
+ }
+
+ if (!reg_d) {
+ D_EXEC(qemu_log("%04d %8s R%03d, R%03d <L=%d, E=%04d>\n",
+ s->regs[R_PC], opcode_to_str[op], reg_a, reg_b, latency,
+ s->regs[R_PC] + latency));
+ } else {
+ D_EXEC(qemu_log("%04d %8s R%03d, R%03d <L=%d, E=%04d> -> R%03d\n",
+ s->regs[R_PC], opcode_to_str[op], reg_a, reg_b, latency,
+ s->regs[R_PC] + latency, reg_d));
+ }
+
+ if (op == OP_VECTOUT) {
+ return 0;
+ }
+
+ /* store output for this cycle */
+ if (reg_d) {
+ uint32_t val = output_queue_remove(s);
+ D_EXEC(qemu_log("R%03d <- 0x%08x\n", reg_d, val));
+ s->gp_regs[reg_d] = val;
+ }
+
+ output_queue_advance(s);
+
+ /* store op output */
+ if (op != OP_NOP) {
+ output_queue_insert(s, r, latency-1);
+ }
+
+ /* advance PC */
+ s->regs[R_PC]++;
+
+ return 1;
+};
+
+static void pfpu_start(MilkymistPFPUState *s)
+{
+ int x, y;
+ int i;
+
+ for (y = 0; y <= s->regs[R_VMESHLAST]; y++) {
+ for (x = 0; x <= s->regs[R_HMESHLAST]; x++) {
+ D_EXEC(qemu_log("\nprocessing x=%d y=%d\n", x, y));
+
+ /* set current position */
+ s->gp_regs[GPR_X] = x;
+ s->gp_regs[GPR_Y] = y;
+
+ /* run microcode on this position */
+ i = 0;
+ while (pfpu_decode_insn(s)) {
+ /* decode at most MICROCODE_WORDS instructions */
+ if (i++ >= MICROCODE_WORDS) {
+ error_report("milkymist_pfpu: too many instructions "
+ "executed in microcode. No VECTOUT?\n");
+ break;
+ }
+ }
+
+ /* reset pc for next run */
+ s->regs[R_PC] = 0;
+ }
+ }
+
+ s->regs[R_VERTICES] = x * y;
+
+ trace_milkymist_pfpu_pulse_irq();
+ qemu_irq_pulse(s->irq);
+}
+
+static inline int get_microcode_address(MilkymistPFPUState *s, uint32_t addr)
+{
+ return (512 * s->regs[R_CODEPAGE]) + addr - MICROCODE_BEGIN;
+}
+
+static uint32_t pfpu_read(void *opaque, target_phys_addr_t addr)
+{
+ MilkymistPFPUState *s = opaque;
+ uint32_t r = 0;
+
+ addr >>= 2;
+ switch (addr) {
+ case R_CTL:
+ case R_MESHBASE:
+ case R_HMESHLAST:
+ case R_VMESHLAST:
+ case R_CODEPAGE:
+ case R_VERTICES:
+ case R_COLLISIONS:
+ case R_STRAYWRITES:
+ case R_LASTDMA:
+ case R_PC:
+ case R_DREGBASE:
+ case R_CODEBASE:
+ r = s->regs[addr];
+ break;
+ case GPR_BEGIN ... GPR_END:
+ r = s->gp_regs[addr - GPR_BEGIN];
+ break;
+ case MICROCODE_BEGIN ... MICROCODE_END:
+ r = s->microcode[get_microcode_address(s, addr)];
+ break;
+
+ default:
+ error_report("milkymist_pfpu: read access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+
+ trace_milkymist_pfpu_memory_read(addr << 2, r);
+
+ return r;
+}
+
+static void
+pfpu_write(void *opaque, target_phys_addr_t addr, uint32_t value)
+{
+ MilkymistPFPUState *s = opaque;
+
+ trace_milkymist_pfpu_memory_write(addr, value);
+
+ addr >>= 2;
+ switch (addr) {
+ case R_CTL:
+ if (value & CTL_START_BUSY) {
+ pfpu_start(s);
+ }
+ break;
+ case R_MESHBASE:
+ case R_HMESHLAST:
+ case R_VMESHLAST:
+ case R_CODEPAGE:
+ case R_VERTICES:
+ case R_COLLISIONS:
+ case R_STRAYWRITES:
+ case R_LASTDMA:
+ case R_PC:
+ case R_DREGBASE:
+ case R_CODEBASE:
+ s->regs[addr] = value;
+ break;
+ case GPR_BEGIN ... GPR_END:
+ s->gp_regs[addr - GPR_BEGIN] = value;
+ break;
+ case MICROCODE_BEGIN ... MICROCODE_END:
+ s->microcode[get_microcode_address(s, addr)] = value;
+ break;
+
+ default:
+ error_report("milkymist_pfpu: write access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+}
+
+static CPUReadMemoryFunc * const pfpu_read_fn[] = {
+ NULL,
+ NULL,
+ &pfpu_read,
+};
+
+static CPUWriteMemoryFunc * const pfpu_write_fn[] = {
+ NULL,
+ NULL,
+ &pfpu_write,
+};
+
+static void milkymist_pfpu_reset(DeviceState *d)
+{
+ MilkymistPFPUState *s = container_of(d, MilkymistPFPUState, busdev.qdev);
+ int i;
+
+ for (i = 0; i < R_MAX; i++) {
+ s->regs[i] = 0;
+ }
+ for (i = 0; i < 128; i++) {
+ s->gp_regs[i] = 0;
+ }
+ for (i = 0; i < MICROCODE_WORDS; i++) {
+ s->microcode[i] = 0;
+ }
+ s->output_queue_pos = 0;
+ for (i = 0; i < MAX_LATENCY; i++) {
+ s->output_queue[i] = 0;
+ }
+}
+
+static int milkymist_pfpu_init(SysBusDevice *dev)
+{
+ MilkymistPFPUState *s = FROM_SYSBUS(typeof(*s), dev);
+ int pfpu_regs;
+
+ sysbus_init_irq(dev, &s->irq);
+
+ pfpu_regs = cpu_register_io_memory(pfpu_read_fn, pfpu_write_fn, s,
+ DEVICE_NATIVE_ENDIAN);
+ sysbus_init_mmio(dev, MICROCODE_END * 4, pfpu_regs);
+
+ return 0;
+}
+
+static const VMStateDescription vmstate_milkymist_pfpu = {
+ .name = "milkymist-pfpu",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .minimum_version_id_old = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT32_ARRAY(regs, MilkymistPFPUState, R_MAX),
+ VMSTATE_UINT32_ARRAY(gp_regs, MilkymistPFPUState, 128),
+ VMSTATE_UINT32_ARRAY(microcode, MilkymistPFPUState, MICROCODE_WORDS),
+ VMSTATE_INT32(output_queue_pos, MilkymistPFPUState),
+ VMSTATE_UINT32_ARRAY(output_queue, MilkymistPFPUState, MAX_LATENCY),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static SysBusDeviceInfo milkymist_pfpu_info = {
+ .init = milkymist_pfpu_init,
+ .qdev.name = "milkymist-pfpu",
+ .qdev.size = sizeof(MilkymistPFPUState),
+ .qdev.vmsd = &vmstate_milkymist_pfpu,
+ .qdev.reset = milkymist_pfpu_reset,
+};
+
+static void milkymist_pfpu_register(void)
+{
+ sysbus_register_withprop(&milkymist_pfpu_info);
+}
+
+device_init(milkymist_pfpu_register)
generated by cgit v1.2.3 (git 2.26.2) at 2024-11-27 04:15:30 +0000