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# setjmp/longjmp for Renesas RX.
# 
# The jmpbuf looks like this:
#       
# Register      jmpbuf offset
# R0            0x0
# R1            0x4
# R2            0x8
# R3            0xc
# R4            0x10
# R5            0x14
# R6            0x18
# R7            0x1c
# R8            0x20
# R9            0x24
# R10           0x28
# R11           0x2c
# R12           0x30
# R13           0x34
# R14           0x38
# R15           0x3c
# PC            0x40
#
# R1 contains the pointer to jmpbuf:
#
#       int R1 = setjmp (jmp_buf R1)
#       void longjmp (jmp_buf R1, int R2)
#
# The ABI allows for R1-R5 to be clobbered by functions.  We must be
# careful to always leave the stack in a usable state in case an
# interrupt happens.

        .text
        .global _setjmp
        .type   _setjmp, @function
_setjmp:
        mov.l   r0, [r1]        ; save all the general registers
        mov.l   r1, 0x4[r1]     ; longjmp won't use this, but someone else might.
        mov.l   r2, 0x8[r1]
        mov.l   r3, 0xc[r1]
        mov.l   r4, 0x10[r1]
        mov.l   r5, 0x14[r1]
        mov.l   r6, 0x18[r1]
        mov.l   r7, 0x1c[r1]
        mov.l   r8, 0x20[r1]
        mov.l   r9, 0x24[r1]
        mov.l   r10, 0x28[r1]
        mov.l   r11, 0x2c[r1]
        mov.l   r12, 0x30[r1]
        mov.l   r13, 0x34[r1]
        mov.l   r14, 0x38[r1]
        mov.l   r15, 0x3c[r1]
        mov.l   [r0], r2        ; get return address off the stack
        mov.l   r2, 0x40[r1]    ; PC
        mov     #0, r1          ; Return 0.
        rts
.Lend1:
        .size   _setjmp, .Lend1 - _setjmp


        .global _longjmp
        .type   _longjmp, @function
_longjmp:
        tst     r2, r2          ; Set the Z flag if r2 is 0.
        stz     #1, r2          ; If the Z flag was set put 1 into the return register.
        mov     r2, 4[r1]       ; Put r2 (our return value) into the setjmp buffer as r1.

        mov.l   [r1], r0        ; Restore the stack - there's a slot for PC
        mov.l   0x40[r1], r2    ; Get the saved PC
        mov.l   r2, [r0]        ; Overwrite the old return address

        mov.l   0x3c[r1], r15
        mov.l   0x38[r1], r14
        mov.l   0x34[r1], r13
        mov.l   0x30[r1], r12
        mov.l   0x2c[r1], r11
        mov.l   0x28[r1], r10
        mov.l   0x24[r1], r9
        mov.l   0x20[r1], r8
        mov.l   0x1c[r1], r7
        mov.l   0x18[r1], r6
        mov.l   0x14[r1], r5
        mov.l   0x10[r1], r4
        mov.l   0xc[r1], r3
        mov.l   0x8[r1], r2
        mov.l   0x4[r1], r1     ; This sets up the new return value
        rts
.Lend2:
        .size   _longjmp, .Lend2 - _longjmp