mirror of
https://github.com/autc04/Retro68.git
synced 2024-12-04 16:50:57 +00:00
90 lines
1.9 KiB
ArmAsm
90 lines
1.9 KiB
ArmAsm
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# setjmp/longjmp for Renesas RX.
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#
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# The jmpbuf looks like this:
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#
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# Register jmpbuf offset
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# R0 0x0
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# R1 0x4
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# R2 0x8
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# R3 0xc
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# R4 0x10
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# R5 0x14
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# R6 0x18
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# R7 0x1c
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# R8 0x20
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# R9 0x24
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# R10 0x28
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# R11 0x2c
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# R12 0x30
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# R13 0x34
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# R14 0x38
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# R15 0x3c
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# PC 0x40
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#
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# R1 contains the pointer to jmpbuf:
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#
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# int R1 = setjmp (jmp_buf R1)
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# void longjmp (jmp_buf R1, int R2)
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#
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# The ABI allows for R1-R5 to be clobbered by functions. We must be
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# careful to always leave the stack in a usable state in case an
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# interrupt happens.
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.text
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.global _setjmp
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.type _setjmp, @function
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_setjmp:
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mov.l r0, [r1] ; save all the general registers
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mov.l r1, 0x4[r1] ; longjmp won't use this, but someone else might.
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mov.l r2, 0x8[r1]
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mov.l r3, 0xc[r1]
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mov.l r4, 0x10[r1]
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mov.l r5, 0x14[r1]
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mov.l r6, 0x18[r1]
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mov.l r7, 0x1c[r1]
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mov.l r8, 0x20[r1]
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mov.l r9, 0x24[r1]
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mov.l r10, 0x28[r1]
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mov.l r11, 0x2c[r1]
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mov.l r12, 0x30[r1]
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mov.l r13, 0x34[r1]
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mov.l r14, 0x38[r1]
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mov.l r15, 0x3c[r1]
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mov.l [r0], r2 ; get return address off the stack
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mov.l r2, 0x40[r1] ; PC
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mov #0, r1 ; Return 0.
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rts
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.Lend1:
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.size _setjmp, .Lend1 - _setjmp
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.global _longjmp
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.type _longjmp, @function
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_longjmp:
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tst r2, r2 ; Set the Z flag if r2 is 0.
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stz #1, r2 ; If the Z flag was set put 1 into the return register.
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mov r2, 4[r1] ; Put r2 (our return value) into the setjmp buffer as r1.
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mov.l [r1], r0 ; Restore the stack - there's a slot for PC
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mov.l 0x40[r1], r2 ; Get the saved PC
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mov.l r2, [r0] ; Overwrite the old return address
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mov.l 0x3c[r1], r15
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mov.l 0x38[r1], r14
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mov.l 0x34[r1], r13
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mov.l 0x30[r1], r12
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mov.l 0x2c[r1], r11
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mov.l 0x28[r1], r10
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mov.l 0x24[r1], r9
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mov.l 0x20[r1], r8
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mov.l 0x1c[r1], r7
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mov.l 0x18[r1], r6
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mov.l 0x14[r1], r5
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mov.l 0x10[r1], r4
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mov.l 0xc[r1], r3
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mov.l 0x8[r1], r2
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mov.l 0x4[r1], r1 ; This sets up the new return value
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rts
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.Lend2:
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.size _longjmp, .Lend2 - _longjmp
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