diff options
Diffstat (limited to 'amd64.e')
| -rw-r--r-- | amd64.e | 49 |
1 files changed, 45 insertions, 4 deletions
diff --git a/amd64.e b/amd64.e index ba78bc4..1a5df04 100644 --- a/amd64.e +++ b/amd64.e @@ -518,10 +518,24 @@ s" :cc-greater" keyword 0 4 :rsp reg64 sib ~ : drop-subitem } if + ~ The displacement byte. + ~ + ~ When addressing-disp8-reg64 references a source, as in + ~ lea-reg64-disp8-reg64, the first two parameters of the assembly word + ~ calling it are the source register and the source displacement value. When + ~ it references a target or destination, as in mov-disp8-reg64-reg64, the + ~ LAST two parameters are the target registera and target displacement + ~ value. + ~ + ~ In both cases, the register comes first and the displacement value + ~ comes second. When these are used in a comment template without any other + ~ rearranging going on, whichever is on the top of the stack will be popped + ~ off first. So, we swap them here, thus putting the register on the top. swap ~ : 1 adjust-length ~ : provide-hex8 + ~ : swap-subitems pack8 ; ~ (output point, reg/op field value, reg/mem field register, @@ -538,10 +552,13 @@ s" :cc-greater" keyword 0 4 :rsp reg64 sib ~ : drop-subitem } if - ~ The displacement value. + + ~ The displacement value. This is subject to the same considerations as in + ~ addressing-disp8-reg64. swap ~ : 4 adjust-length ~ : provide-hex32 + ~ : swap-subitems pack32 ; ~ (output point, reg/op field value, @@ -552,7 +569,17 @@ s" :cc-greater" keyword dup :rbp != { ~ Reg/mem value 4 means to use an SIB byte (at least, with this mode). 5 roll 0 6 roll 4 modrm 4 unroll - reg64 3unroll reg64 3unroll scalefield 3unroll sib + reg64 3unroll reg64 3unroll scalefield 3unroll + ~ We want the scale factor to show after the registers, so we put it + ~ last on the stack. We also want the base register to show before the + ~ index register, so the base comes first. + ~ + ~ Importantly, we have to do this before the sib so it'll count as being + ~ inside the span the assembly word's description attaches to. + ~ + ~ : -3 roll-subitems + ~ : swap-subitems + sib exit } if ." Base parameter to addressing-indexed-reg64 is :rbp." 1 sys-exit ; @@ -568,7 +595,21 @@ s" :cc-greater" keyword swap ~ : 1 adjust-length ~ : provide-hex8 - pack8 ; + ~ + ~ We want the parameters to be shown in the order: + ~ + ~ base register, index register, index scale factor, displacement + ~ + ~ So, we put them on the stack in the opposite of that order. + ~ + ~ Importantly, we have to do this before the pack8 so it'll count as being + ~ inside the span the assembly word's description attaches to. + ~ + ~ : -4 roll-subitems + ~ : -3 roll-subitems + ~ : swap-subitems + pack8 + ; ~ Easy instructions @@ -687,7 +728,7 @@ s" :cc-greater" keyword ~ (output point, source register, target register -- output point) : mov-reg64-reg64 - ~ : 1 #swap # # mov-reg64-reg64 + ~ : 1 # # mov-reg64-reg64 3roll rex-w 0x89 pack8 3unroll swap reg64 swap addressing-reg64 ; : mov-indirect-reg64-reg64 |