diff options
Diffstat (limited to 'cpu/cpu.ml')
| -rw-r--r-- | cpu/cpu.ml | 88 |
1 files changed, 72 insertions, 16 deletions
@@ -9,25 +9,62 @@ let one n = let two n = const "01" ++ zeroes (n-2) +let ser_out, set_ser_out = loop 8 +let ser_in_busy, set_ser_in_busy = loop 1 let cpu_ram ra we wa d = (* Ram chip has word size = 8 bits and address size = 16 bits 0x0000 to 0x3FFF is ROM0 - 0x4000 to 0x7FFF is unused, reserved for MMIO + 0x4000 to 0x7FFF is MMIO : + byte 0x4000 is clock ticker (increments by one every tick ; zeroed on read) + byte 0x4100 is serial input (zeroed on read) + byte 0x4102 is serial output 0x8000 to 0xFFFF is RAM *) + let read_data = zeroes 8 in + let ra_hi1 = ra ** 15 in let ra_lo1 = ra % (0, 14) in let ra_hi2 = ra ** 14 in let ra_lo2 = ra % (0, 13) in let read_rom = (not ra_hi1) ^& (not ra_hi2) in + let rd_rom = rom "ROM0" 14 8 ra_lo2 in + let read_data = mux read_rom read_data rd_rom in + + let read_ram = ra_hi1 in let wa_hi1 = wa ** 15 in let wa_lo1 = wa % (0, 14) in let we_ram = we ^& wa_hi1 in - - let rd_rom = rom "ROM0" 14 8 ra_lo2 in let rd_ram = ram 15 8 ra_lo1 we_ram wa_lo1 d in - mux read_ram (mux read_rom (zeroes 8) rd_rom) rd_ram + let read_data = mux read_ram read_data rd_ram in + + let read_tick = eq_c 16 ra 0x4000 in + let next_tick, set_next_tick = loop 8 in + let tick = reg 8 next_tick in + let tick_d = sign_extend 1 8 (get "tick") in + let read_data = + set_next_tick (mux read_tick (nadder_nocarry 8 tick tick_d) tick_d) ^. + mux read_tick read_data tick in + + let write_ser = we ^& (eq_c 16 wa 0x4102) in + let read_data = + set_ser_out (mux write_ser (zeroes 8) d) ^. + read_data in + + let read_ser = eq_c 16 ra 0x4000 in + let next_ser, set_next_ser = loop 8 in + let ser = reg 8 next_ser in + let ser_in = get "ser_in" in + let iser = nonnull 8 ser_in in + let ser = mux iser ser ser_in in + let ser_busy = nonnull 8 ser in + let read_data = + set_ser_in_busy ser_busy ^. + set_next_ser ser ^. + mux read_ser read_data ser in + + read_data + let r0 = zeroes 16 let r1, save_r1 = loop 16 @@ -65,17 +102,6 @@ let save_cpu_regs wr wd = save_r7 (reg 16 next_r7) ^. r0 -(* -let ticker n = - let k, save_k = loop n in - let s = reg n k in - let next = nadder_nocarry n s (one n) in - ignore (save_k next) s - -let tick1 = ticker 1 -let tick2 = ticker 2 -*) - let rl, rh, i, ex, exf, pc = let next_read, save_next_read = loop 1 in let read = not (reg 1 (not next_read)) in @@ -123,10 +149,21 @@ let rl, rh, i, ex, exf, pc = let wr = zeroes 3 in let rwd = zeroes 16 in + (* instruction : se/sne/slt/slte/sleu/sleu *) + let instr_sxxx = exec ^& (eq_c 4 (i_i % (1, 4)) 0b0010) in + let f0 = i_i ** 0 in + let cond_sxxx = alu_comparer 16 f0 i_f v_ra v_rb in + let wr = mux instr_sxxx wr i_r in + let rwd = mux instr_sxxx rwd (mux cond_sxxx (zeroes 16) (one 16)) in + (* instruction : incri *) let instr_incri = exec ^& eq_c 5 i_i 0b00110 in let wr = mux instr_incri wr i_r in let rwd = mux instr_incri rwd (nadder_nocarry 16 v_r (sign_extend 8 16 i_id)) in + (* instruction : shi *) + let instr_shi = exec ^& eq_c 5 i_i 0b00111 in + let wr = mux instr_shi wr i_r in + let rwd = mux instr_shi rwd (npshift_signed 16 8 v_r i_id) in (* instruction : j *) let instr_j = exec ^& eq_c 5 i_i 0b01000 in @@ -147,6 +184,11 @@ let rl, rh, i, ex, exf, pc = let wr = mux instr_jalxx wr (const "011") in let rwd = mux instr_jalxx rwd next_pc in + (* instruction : lra *) + let instr_lra = exec ^& eq_c 5 i_i 0b01100 in + let wr = mux instr_lra wr (const "101") in + let rwd = mux instr_lra rwd (nadder_nocarry 16 pc (sign_extend 11 16 i_jd)) in + (* instruction : lw/lwr/sw/swr *) let instr_lsw = eq_c 4 (i_i % (1, 4)) 0b1000 in let instr_lswr = eq_c 4 (i_i % (1, 4)) 0b1010 in @@ -178,6 +220,15 @@ let rl, rh, i, ex, exf, pc = let d = mux swx_save_hi d (v_r % (8, 15)) in let exec_finished = mux instr_lwx exec_finished swx_save_hi in + (* instruction : lil/lilz/liu/liuz *) + let instr_lixx = eq_c 3 (i_i % (2, 4))0b110 in + let instr_lixz = i ** 0 in + let instr_liux = i ** 1 in + let wr = mux instr_lixx wr i_r in + let rwd = mux instr_lixx rwd + (mux instr_liux + ( (* lil *) i_id ++ (mux instr_lixz (v_r % (8, 15)) (zeroes 8)) ) + ( (* liu *) (mux instr_lixz (v_r % (0, 7)) (zeroes 8)) ++ i_id)) in save_cpu_regs wr rwd ^. save_ram_read (cpu_ram ra we wa d) ^. @@ -187,7 +238,10 @@ let rl, rh, i, ex, exf, pc = let p = program - [] + [ + "tick", 1; + "ser_in", 8; + ] [ "read_ilow", 1, rl; "read_ihi", 1, rh; @@ -203,6 +257,8 @@ let p = "r5_E", 16, r5; "r6_F", 16, r6; "r7_G", 16, r7; + "ser_out", 8, ser_out; + "ser_in_busy", 1, ser_in_busy; ] let () = Netlist_gen.print stdout p |