145 lines
7.3 KiB
NASM
145 lines
7.3 KiB
NASM
;; Standard Library
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;; These registers are used within virtual functions as temporary holders
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.constant std_SCRATCH_0 MGMT_SCRATCH_0
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.constant std_SCRATCH_1 MGMT_SCRATCH_1
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;; Also used as single return value
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.reserve std_RETURN_VALUE 0x1E0
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.reserve std_RETURN_VALUE_EXTRA 0x1E1
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.reserve std_PARAMETER_0 0x1E2
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.reserve std_PARAMETER_1 0x1E3
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.constant RRET std_RETURN_VALUE ;;Alias
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.constant RRET_X std_RETURN_VALUE_EXTRA ;;Alias
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.constant P0 std_PARAMETER_0
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.constant P1 std_PARAMETER_1
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;; These are offset registers to be called with <OP>~2 to access stack frame parameters
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.constant P2 %0, +1 ;; Equivalent to same address in GET <Reg>, 1
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.constant P3 %0, +2 ;; Equivalent to same address in GET <Reg>, 2
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.constant P4 %0, +3 ;; Equivalent to same address in GET <Reg>, 3
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.constant P5 %0, +4 ;; Equivalent to same address in GET <Reg>, 4
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.constant P6 %0, +5 ;; Equivalent to same address in GET <Reg>, 5
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.constant P7 %0, +6 ;; Equivalent to same address in GET <Reg>, 6
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.constant P8 %0, +7 ;; Equivalent to same address in GET <Reg>, 7
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.constant P9 %0, +8 ;; Equivalent to same address in GET <Reg>, 8
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.constant P10 %0, +9 ;; Equivalent to same address in GET <Reg>, 9
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.constant P11 %0, +10 ;; Equivalent to same address in GET <Reg>, 10
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.constant P12 %0, +11 ;; Equivalent to same address in GET <Reg>, 11
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.constant P13 %0, +12 ;; Equivalent to same address in GET <Reg>, 12
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.constant P14 %0, +13 ;; Equivalent to same address in GET <Reg>, 13
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.constant P15 %0, +14 ;; Equivalent to same address in GET <Reg>, 14
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.constant P16 %0, +15 ;; Equivalent to same address in GET <Reg>, 15
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;; These are parameter registers to be called with GET to access stack frame parameters
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.constant GET_P2 1
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.constant GET_P3 2
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.constant GET_P4 3
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.constant GET_P5 4
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.constant GET_P6 5
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.constant GET_P7 6
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.constant GET_P8 7
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.constant GET_P9 8
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.constant GET_P10 9
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.constant GET_P11 10
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.constant GET_P12 11
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.constant GET_P13 12
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.constant GET_P14 13
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.constant GET_P15 14
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.constant GET_P16 15
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;; Ephemeral registers to be used within functions. These values may not be kept when calling other functions. They can be used when returning values if necessary.
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;; Some std functions might restore these values.
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.reserve std_EPHEMERAL_REGISTER_0 0x1F0
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.constant std_EPHEMERAL_REGISTER_1 0x1F1
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.reserve std_EPHEMERAL_REGISTER_2 0x1F2
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.reserve std_EPHEMERAL_REGISTER_3 0x1F3
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.reserve std_EPHEMERAL_REGISTER_4 0x1F4
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.reserve std_EPHEMERAL_REGISTER_5 0x1F5
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.reserve std_EPHEMERAL_REGISTER_6 0x1F6
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.reserve std_EPHEMERAL_REGISTER_7 0x1F7
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.reserve std_EPHEMERAL_REGISTER_8 0x1F8
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.reserve std_EPHEMERAL_REGISTER_9 0x1F9
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.reserve std_EPHEMERAL_REGISTER_10 0x1FA
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.reserve std_EPHEMERAL_REGISTER_11 0x1FB
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.reserve std_EPHEMERAL_REGISTER_12 0x1FC
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.reserve std_EPHEMERAL_REGISTER_13 0x1FD
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.reserve std_EPHEMERAL_REGISTER_14 0x1FE
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.reserve std_EPHEMERAL_REGISTER_15 0x1FF
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;; Abbreviations
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.constant R0 std_EPHEMERAL_REGISTER_0
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.constant R1 std_EPHEMERAL_REGISTER_1
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.constant R2 std_EPHEMERAL_REGISTER_2
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.constant R3 std_EPHEMERAL_REGISTER_3
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.constant R4 std_EPHEMERAL_REGISTER_4
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.constant R5 std_EPHEMERAL_REGISTER_5
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.constant R6 std_EPHEMERAL_REGISTER_6
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.constant R7 std_EPHEMERAL_REGISTER_7
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.constant R8 std_EPHEMERAL_REGISTER_8
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.constant R9 std_EPHEMERAL_REGISTER_9
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.constant R10 std_EPHEMERAL_REGISTER_10
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.constant R11 std_EPHEMERAL_REGISTER_11
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.constant R12 std_EPHEMERAL_REGISTER_12
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.constant R13 std_EPHEMERAL_REGISTER_13
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.constant R14 std_EPHEMERAL_REGISTER_14
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.constant R15 std_EPHEMERAL_REGISTER_15
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; FASTCALL uint std_multiply(uint A, uint B). Return value on RRET
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; Uses simple addition
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; TODO: use add + shift
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.constant std_mul @std_multiply
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.constant std_multiply @std_multiply
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std_multiply:
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PUSH BSM_COUNTER_0 ; Save old value of counter
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MOV BSM_COUNTER_0, P0 ; Move A to counter
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MOV RRET, 0
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JUMP @.loop ; Skip first iteration
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.multiply:
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ADD RRET, RRET, P1 ; Add B to itself A times
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.loop: LOOP @.multiply ; Check if 0, if not, decrease A and go back. Use COUNTER[0]
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POP BSM_COUNTER_0 ; Restore old value of counter
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RET ; Return, no need to get rid of stack as fastcall passed them on registers
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; FASTCALL uint std_divide(uint dividend, uint divisor). Return quotient on RRET, remainder on RRET_X
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; Uses shift + add division
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; TODO: check validity
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.constant std_div @std_divide
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.constant std_divide @std_divide
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std_divide:
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BNE P1, 0, 0xffffffff, @.normal_division ; Handle divisor = 0
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WRITE RRET, 0xffffffff, 0xffffffff ; Return both values 0xffffffff
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JUMP @.return
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.normal_division:
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PUSH BSM_COUNTER_0 ; Save old value of counter
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MOV BSM_COUNTER_0, 32 ; Move bits left to counter (8 * 4)
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MOV RRET, P0 ; Move dividend to RRET (quotient)
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MOV RRET_X, 0 ; Move remainder to RRET_X
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MOV R0, 0
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.divide:
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MOV R0, RRET ; Move quotient to temp R0
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ADD RRET, RRET, RRET ; quotient = quotient + quotient
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ADD RRET_X, RRET_X, RRET_X ; remainder = remainder + remainder + ...
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SHL R0, RRET, R0 ; quot << R0
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ADD RRET_X, RRET_X, R0 ; remainder = ... + (quot << R0)
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SUB R0, RRET_X, P1 ; compare rem >= divisor
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BNE R0, 0, 1 <31, @.no_reduce
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SUB RRET_X, RRET_X, P1 ; remainder = remainder - divisor
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ADD RRET, RRET, 1 ; quotient = quotient + 1
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.no_reduce:
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LOOP @.divide ; Check if 0, if not, decrease bits left and go back. Use COUNTER[0]
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POP BSM_COUNTER_0 ; Restore old value of counter
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.return: RET ; Return, no need to get rid of stack as fastcall passed them on registers
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;; x86-like definitions
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.constant ebp, rrcc_FRAME_POINTER
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.constant esp, rrcc_STACK_POINTER
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.constant eax, RRET |