} UNSAFE_END
UNSAFE_ENTRY(void, Unsafe_PutLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x)) {
if (VM_Version::supports_cx8()) {
MemoryAccess(thread, obj, offset).put_volatile<jlong>(x);
} else {
MemoryAccess(thread, obj, offset).put_jlong_locked(x);
}
} UNSAFE_END
} UNSAFE_END
#ifndef SUPPORTS_NATIVE_CX8
// VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
//
// On platforms which do not support atomic compare-and-swap of jlong (8 byte)
// values we have to use a lock-based scheme to enforce atomicity. This has to be
// applied to all Unsafe operations that set the value of a jlong field. Even so
// the compareAndSwapLong operation will not be atomic with respect to direct stores
// to the field from Java code. It is important therefore that any Java code that
// utilizes these Unsafe jlong operations does not perform direct stores. To permit
// direct loads of the field from Java code we must also use Atomic::store within the
// locked regions. And for good measure, in case there are direct stores, we also
// employ Atomic::load within those regions. Note that the field in question must be
// volatile and so must have atomic load/store accesses applied at the Java level.
//
// The locking scheme could utilize a range of strategies for controlling the locking
// granularity: from a lock per-field through to a single global lock. The latter is
// the simplest and is used for the current implementation. Note that the Java object
// that contains the field, can not, in general, be used for locking. To do so can lead
// to deadlocks as we may introduce locking into what appears to the Java code to be a
// lock-free path.
//
// As all the locked-regions are very short and themselves non-blocking we can treat
// them as leaf routines and elide safepoint checks (ie we don't perform any thread
// state transitions even when blocking for the lock). Note that if we do choose to
// add safepoint checks and thread state transitions, we must ensure that we calculate
// the address of the field _after_ we have acquired the lock, else the object may have
// been moved by the GC
UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
if (VM_Version::supports_cx8()) {
return MemoryAccess(thread, obj, offset).get_volatile<jlong>();
} else {
return MemoryAccess(thread, obj, offset).get_jlong_locked();
}
} UNSAFE_END
int main(int argc, char ** argv)
{
char * binfilename = NULL;
char * srcfilename = NULL;
char * base = NULL;
int i, cycle;
bus32 tmp;
bus8 inst_mem[4096]; /* instruction memory */
bus8 main_mem[4096]; /* main memory */
bus32 gnd; /* ground bus signal */
bus32 pc; /* program counter */
bus32 pc4; /* PC + 4 bus */
bus32 ir; /* instruction register */
bus32 jmp_addr; /* jump bus */
bus32 imm_sext; /* immediate sign extended bus */
bus32 imm_shext; /* immediate sign extended shifted bus */
bus32 branch_addr; /* branch bus */
bus32 mbranch_addr; /* mbranch bus */
/* control unit signals */
wire reg_write, reg_dest;
wire mem_read, mem_write, mem_toreg;
wire jump, branch;
wire alu_src;
bus3 alu_op;
/* register memory signals & controls */
bus32 reg_in, reg_out1, reg_out2;
bus32 reg_write_addr;
/* main memory signal */
bus32 mem_out;
/* alu signals */
wire zero;
bus32 alu_src_val, alu_out;
if (argc == 1) {
fprintf(stderr, "usage: %s <filename>\n", argv[0]);
return -1;
}
srcfilename = argv[1];
base = _parse_filename(srcfilename);
if (!base) return -1;
binfilename = malloc(sizeof(char) * (strlen(base) + 5));
sprintf(binfilename, "%s.bin", base);
printf("assembling %s to %s...\n", srcfilename, binfilename);
if (!Assemble(srcfilename, binfilename)) return -1;
printf("loading %s into memory...\n", binfilename);
LoadMemory(binfilename, inst_mem);
/* load PC with initial VM address of 0x00000000 */
setbus32(gnd, "00000000000000000000000000000000");
setbus32(pc, gnd);
/* initialize memory */
InitializeRegisterFileAccess();
for (i=0; i < 4096; i++) setbus8(main_mem[i], "00000000");
for(cycle=0; ; cycle++)
{
/* load IR with PC value */
MemoryAccess(ir, pc, gnd, '0', inst_mem);
/* report fetched register values */
printf("cycle: %d, PC: %.32s (%d), IR: %.32s\n\t", cycle, pc, bus32toint(pc), ir);
/* halt check */
if (bus32toint(ir) == 0x0000003F) {
printf("\nmachine halted\n");
break;
}
/* PC + 4 data path */
RCAdder_32(pc4, gnd, pc, "00000000000000000000000000000100", '0');
/* jump data path */
shiftleft2x(jmp_addr, ir);
jmp_addr[0] = pc4[0];
jmp_addr[1] = pc4[1];
jmp_addr[2] = pc4[2];
jmp_addr[3] = pc4[3];
/* sign extended / shifted immediate data path */
signextend(imm_sext, &ir[16]);
shiftleft2x(imm_shext, imm_sext);
/* control unit data path */
ControlUnit(ir, &ir[26], ®_write, ®_dest,
&mem_read, &mem_write, &mem_toreg,
&jump, &branch, &alu_src, alu_op);
/* register memory data path - read */
Mux2_5(reg_write_addr, &ir[11], &ir[16], reg_dest);
RegisterFileAccess(®_out1, ®_out2, &ir[6], &ir[11], reg_write_addr, reg_in, '0');
/* alu data path */
Mux2_32(alu_src_val, reg_out2, imm_sext, alu_src);
zero = ALU(&alu_out, reg_out1, alu_src_val, alu_op);
/* branch data path */
RCAdder_32(branch_addr, gnd, pc4, imm_shext, '0');
Mux2_32(mbranch_addr, pc4, branch_addr, AND2_1(zero, branch));
Mux2_32(pc, mbranch_addr, jmp_addr, jump);
/* main memory data path */
MemoryAccess(mem_out, alu_out, reg_out2, mem_write, main_mem);
Mux2_32(reg_in, alu_out, mem_out, mem_toreg);
/* register memory data path - write */
RegisterFileAccess(®_out1, ®_out2, &ir[6], &ir[11], reg_write_addr, reg_in, reg_write);
/* dump register memory and signal information */
for (i=0; i < 14; i++) {
inttobusn(i, 5, tmp);
RegisterFileAccess(®_out1, ®_out2, tmp, &ir[11], reg_write_addr, reg_in, '0');
printf("R%d: %d, ", i, bus32toint(reg_out1));
}
printf("\b\b\n\tbranch_addr = %.32s (%d) jmp_addr = %.32s (%d)\n",
branch_addr, bus32toint(branch_addr), jmp_addr, bus32toint(jmp_addr));
printf("\topcode = %.6s, imm_sext = %.32s (%d), imm_shext = %.32s (%d), PC+4 = %.32s (%d)\n",
ir, imm_sext, bus32toint(imm_sext), imm_shext, bus32toint(imm_shext), pc4, bus32toint(pc4));
printf("\treg_write = %c, reg_dest = %c, mem_read = %c, mem_write = %c, mem_toreg = %c, jump = %c, branch = %c, alu_src = %c, alu_op = %.3s, zero = %c\n",
reg_write, reg_dest, mem_read, mem_write, mem_toreg, jump, branch, alu_src, alu_op, zero);
getchar();
}
printf("\ntotal no. cycles: %d\n", cycle);
// report end of program information
free(binfilename);
}
