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<span class="SalientComment">## Mu's instructions and their table-driven translation</span>
See <a href="http://akkartik.name/akkartik-convivial-20200315.pdf">http://akkartik.name/akkartik-convivial-20200315.pdf</a> for the complete
story. In brief: Mu is a statement-oriented language. Blocks consist of flat
lists of instructions. Instructions can have inputs after the operation, and
outputs to the left of a '<span class="Special"><-</span>'. Inputs and outputs must be variables. They can't
include nested expressions. Variables can be literals ('n'), or live in a
register ('var/reg') or in memory ('var') at some 'stack-offset' from the 'ebp'
register. Outputs must be registers. To modify a variable in memory, pass it in
by reference as an input. (Inputs are more precisely called 'inouts'.)
Conversely, registers that are just read from must not be passed as inputs.
The following chart shows all the instruction forms supported by Mu, along with
the SubX instruction they're translated to.
var/<span class="Constant">eax</span> <span class="Special"><-</span> increment => <span class="Constant">"40/increment-eax"</span>
var/<span class="Constant">ecx</span> <span class="Special"><-</span> increment => <span class="Constant">"41/increment-ecx"</span>
var/<span class="Constant">edx</span> <span class="Special"><-</span> increment => <span class="Constant">"42/increment-edx"</span>
var/<span class="Constant">ebx</span> <span class="Special"><-</span> increment => <span class="Constant">"43/increment-ebx"</span>
var/<span class="Constant">esi</span> <span class="Special"><-</span> increment => <span class="Constant">"46/increment-esi"</span>
var/<span class="Constant">edi</span> <span class="Special"><-</span> increment => <span class="Constant">"47/increment-edi"</span>
increment var => <span class="Constant">"ff 0/subop/increment *(ebp+"</span> var.stack-offset <span class="Constant">")"</span>
increment *var/reg => <span class="Constant">"ff 0/subop/increment *"</span> reg
var/<span class="Constant">eax</span> <span class="Special"><-</span> decrement => <span class="Constant">"48/decrement-eax"</span>
var/<span class="Constant">ecx</span> <span class="Special"><-</span> decrement => <span class="Constant">"49/decrement-ecx"</span>
var/<span class="Constant">edx</span> <span class="Special"><-</span> decrement => <span class="Constant">"4a/decrement-edx"</span>
var/<span class="Constant">ebx</span> <span class="Special"><-</span> decrement => <span class="Constant">"4b/decrement-ebx"</span>
var/<span class="Constant">esi</span> <span class="Special"><-</span> decrement => <span class="Constant">"4e/decrement-esi"</span>
var/<span class="Constant">edi</span> <span class="Special"><-</span> decrement => <span class="Constant">"4f/decrement-edi"</span>
decrement var => <span class="Constant">"ff 1/subop/decrement *(ebp+"</span> var.stack-offset <span class="Constant">")"</span>
decrement *var/reg => <span class="Constant">"ff 1/subop/decrement *"</span> reg
var/reg <span class="Special"><-</span> add var2/reg2 => <span class="Constant">"01/add-to %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> add var2 => <span class="Constant">"03/add *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> add *var2/reg2 => <span class="Constant">"03/add *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
add-to var1, var2/reg => <span class="Constant">"01/add-to *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> add n => <span class="Constant">"05/add-to-eax "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> add n => <span class="Constant">"81 0/subop/add %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
add-to var, n => <span class="Constant">"81 0/subop/add *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
add-to *var/reg, n => <span class="Constant">"81 0/subop/add *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> subtract var2/reg2 => <span class="Constant">"29/subtract-from %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> subtract var2 => <span class="Constant">"2b/subtract *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> subtract *var2/reg2 => <span class="Constant">"2b/subtract *"</span> reg2 <span class="Constant">" "</span> reg1 <span class="Constant">"/r32"</span>
subtract-from var1, var2/reg2 => <span class="Constant">"29/subtract-from *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg2 <span class="Constant">"/r32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> subtract n => <span class="Constant">"2d/subtract-from-eax "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> subtract n => <span class="Constant">"81 5/subop/subtract %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
subtract-from var, n => <span class="Constant">"81 5/subop/subtract *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
subtract-from *var/reg, n => <span class="Constant">"81 5/subop/subtract *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> and var2/reg2 => <span class="Constant">"21/and-with %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> and var2 => <span class="Constant">"23/and *(ebp+"</span> var2.stack-offset <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> and *var2/reg2 => <span class="Constant">"23/and *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
and-with var1, var2/reg => <span class="Constant">"21/and-with *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> and n => <span class="Constant">"25/and-with-eax "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> and n => <span class="Constant">"81 4/subop/and %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
and-with var, n => <span class="Constant">"81 4/subop/and *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
and-with *var/reg, n => <span class="Constant">"81 4/subop/and *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> or var2/reg2 => <span class="Constant">"09/or-with %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> or var2 => <span class="Constant">"0b/or *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> or *var2/reg2 => <span class="Constant">"0b/or *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
or-with var1, var2/reg2 => <span class="Constant">"09/or-with *(ebp+"</span> var1.stack-offset <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> or n => <span class="Constant">"0d/or-with-eax "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> or n => <span class="Constant">"81 1/subop/or %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
or-with var, n => <span class="Constant">"81 1/subop/or *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
or-with *var/reg, n => <span class="Constant">"81 1/subop/or *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> xor var2/reg2 => <span class="Constant">"31/xor-with %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> xor var2 => <span class="Constant">"33/xor *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> xor *var2/reg2 => <span class="Constant">"33/xor *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
xor-with var1, var2/reg => <span class="Constant">"31/xor-with *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> xor n => <span class="Constant">"35/xor-with-eax "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> xor n => <span class="Constant">"81 6/subop/xor %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
xor-with var, n => <span class="Constant">"81 6/subop/xor *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
xor-with *var/reg, n => <span class="Constant">"81 6/subop/xor *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">eax</span> <span class="Special"><-</span> copy n => <span class="Constant">"b8/copy-to-eax "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">ecx</span> <span class="Special"><-</span> copy n => <span class="Constant">"b9/copy-to-ecx "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">edx</span> <span class="Special"><-</span> copy n => <span class="Constant">"ba/copy-to-edx "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">ebx</span> <span class="Special"><-</span> copy n => <span class="Constant">"bb/copy-to-ebx "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">esi</span> <span class="Special"><-</span> copy n => <span class="Constant">"be/copy-to-esi "</span> n <span class="Constant">"/imm32"</span>
var/<span class="Constant">edi</span> <span class="Special"><-</span> copy n => <span class="Constant">"bf/copy-to-edi "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> copy var2/reg2 => <span class="Constant">"89/<- %"</span> reg <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
copy-to var1, var2/reg => <span class="Constant">"89/<- *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> copy var2 => <span class="Constant">"8b/-> *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> copy *var2/reg2 => <span class="Constant">"8b/-> *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> copy n => <span class="Constant">"c7 0/subop/copy %"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
copy-to var, n => <span class="Constant">"c7 0/subop/copy *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
copy-to *var/reg, n => <span class="Constant">"c7 0/subop/copy *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
compare var1, var2/reg2 => <span class="Constant">"39/compare *(ebp+"</span> var1.stack-offset <span class="Constant">") "</span> reg2 <span class="Constant">"/r32"</span>
compare *var1/reg1, var2/reg2 => <span class="Constant">"39/compare *"</span> reg1 <span class="Constant">" "</span> reg2 <span class="Constant">"/r32"</span>
compare var1/reg1, var2 => <span class="Constant">"3b/compare<- *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg1 <span class="Constant">"/r32"</span>
compare var/reg, *var2/reg2 => <span class="Constant">"3b/compare<- *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
compare var/<span class="Constant">eax</span>, n => <span class="Constant">"3d/compare-eax-with "</span> n <span class="Constant">"/imm32"</span>
compare var, n => <span class="Constant">"81 7/subop/compare *(ebp+"</span> var.stack-offset <span class="Constant">") "</span> n <span class="Constant">"/imm32"</span>
compare *var/reg, n => <span class="Constant">"81 7/subop/compare *"</span> reg <span class="Constant">" "</span> n <span class="Constant">"/imm32"</span>
var/reg <span class="Special"><-</span> multiply var2 => <span class="Constant">"0f af/multiply *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> multiply *var2/reg2 => <span class="Constant">"0f af/multiply *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
<span class="PreProc">break</span> => <span class="Constant">"e9/jump break/disp32"</span>
<span class="PreProc">break</span> label => <span class="Constant">"e9/jump "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop</span> => <span class="Constant">"e9/jump loop/disp32"</span>
<span class="PreProc">loop</span> label => <span class="Constant">"e9/jump "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-=</span> => <span class="Constant">"0f 84/jump-if-= break/disp32"</span>
<span class="PreProc">break-if-=</span> label => <span class="Constant">"0f 84/jump-if-= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-=</span> => <span class="Constant">"0f 84/jump-if-= loop/disp32"</span>
<span class="PreProc">loop-if-=</span> label => <span class="Constant">"0f 84/jump-if-= "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-!=</span> => <span class="Constant">"0f 85/jump-if-!= break/disp32"</span>
<span class="PreProc">break-if-!=</span> label => <span class="Constant">"0f 85/jump-if-!= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-!=</span> => <span class="Constant">"0f 85/jump-if-!= loop/disp32"</span>
<span class="PreProc">loop-if-!=</span> label => <span class="Constant">"0f 85/jump-if-!= "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-<</span> => <span class="Constant">"0f 8c/jump-if-< break/disp32"</span>
<span class="PreProc">break-if-<</span> label => <span class="Constant">"0f 8c/jump-if-< "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-<</span> => <span class="Constant">"0f 8c/jump-if-< loop/disp32"</span>
<span class="PreProc">loop-if-<</span> label => <span class="Constant">"0f 8c/jump-if-< "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-></span> => <span class="Constant">"0f 8f/jump-if-> break/disp32"</span>
<span class="PreProc">break-if-></span> label => <span class="Constant">"0f 8f/jump-if-> "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-></span> => <span class="Constant">"0f 8f/jump-if-> loop/disp32"</span>
<span class="PreProc">loop-if-></span> label => <span class="Constant">"0f 8f/jump-if-> "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-<=</span> => <span class="Constant">"0f 8e/jump-if-<= break/disp32"</span>
<span class="PreProc">break-if-<=</span> label => <span class="Constant">"0f 8e/jump-if-<= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-<=</span> => <span class="Constant">"0f 8e/jump-if-<= loop/disp32"</span>
<span class="PreProc">loop-if-<=</span> label => <span class="Constant">"0f 8e/jump-if-<= "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if->=</span> => <span class="Constant">"0f 8d/jump-if->= break/disp32"</span>
<span class="PreProc">break-if->=</span> label => <span class="Constant">"0f 8d/jump-if->= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if->=</span> => <span class="Constant">"0f 8d/jump-if->= loop/disp32"</span>
<span class="PreProc">loop-if->=</span> label => <span class="Constant">"0f 8d/jump-if->= "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-addr<</span> => <span class="Constant">"0f 82/jump-if-addr< break/disp32"</span>
<span class="PreProc">break-if-addr<</span> label => <span class="Constant">"0f 82/jump-if-addr< "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-addr<</span> => <span class="Constant">"0f 82/jump-if-addr< loop/disp32"</span>
<span class="PreProc">loop-if-addr<</span> label => <span class="Constant">"0f 82/jump-if-addr< "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-addr></span> => <span class="Constant">"0f 87/jump-if-addr> break/disp32"</span>
<span class="PreProc">break-if-addr></span> label => <span class="Constant">"0f 87/jump-if-addr> "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-addr></span> => <span class="Constant">"0f 87/jump-if-addr> loop/disp32"</span>
<span class="PreProc">loop-if-addr></span> label => <span class="Constant">"0f 87/jump-if-addr> "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-addr<=</span> => <span class="Constant">"0f 86/jump-if-addr<= break/disp32"</span>
<span class="PreProc">break-if-addr<=</span> label => <span class="Constant">"0f 86/jump-if-addr<= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-addr<=</span> => <span class="Constant">"0f 86/jump-if-addr<= loop/disp32"</span>
<span class="PreProc">loop-if-addr<=</span> label => <span class="Constant">"0f 86/jump-if-addr<= "</span> label <span class="Constant">":loop/disp32"</span>
<span class="PreProc">break-if-addr>=</span> => <span class="Constant">"0f 83/jump-if-addr>= break/disp32"</span>
<span class="PreProc">break-if-addr>=</span> label => <span class="Constant">"0f 83/jump-if-addr>= "</span> label <span class="Constant">":break/disp32"</span>
<span class="PreProc">loop-if-addr>=</span> => <span class="Constant">"0f 83/jump-if-addr>= loop/disp32"</span>
<span class="PreProc">loop-if-addr>=</span> label => <span class="Constant">"0f 83/jump-if-addr>= "</span> label <span class="Constant">":loop/disp32"</span>
In the following instructions types are provided for clarity even if they must
be provided in an earlier 'var' declaration.
<span class="Comment"># Address operations</span>
var/reg: (addr T) <span class="Special"><-</span> address var2: T
=> <span class="Constant">"8d/copy-address *(ebp+"</span> var2.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
<span class="Comment"># Array operations</span>
(TODO: bounds-checking)
var/reg <span class="Special"><-</span> index arr/rega: (addr array T), idx/regi: int
| if size-of(T) is <span class="Constant">4</span> or <span class="Constant">8</span>
=> <span class="Constant">"8d/copy-address *("</span> rega <span class="Constant">"+"</span> regi <span class="Constant">"<<"</span> log2(size-of(T)) <span class="Constant">"+4) "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> index arr: (array T sz), idx/regi: int
=> <span class="Constant">"8d/copy-address *(ebp+"</span> regi <span class="Constant">"<<"</span> log2(size-of(T)) <span class="Constant">"+"</span> (arr.stack-offset + <span class="Constant">4</span>) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> index arr/rega: (addr array T), n
=> <span class="Constant">"8d/copy-address *("</span> rega <span class="Constant">"+"</span> (n*size-of(T)+<span class="Constant">4</span>) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> index arr: (array T sz), n
=> <span class="Constant">"8d/copy-address *(ebp+"</span> (arr.stack-offset+<span class="Constant">4</span>+n*size-of(T)) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg: (offset T) <span class="Special"><-</span> compute-offset arr: (addr array T), idx/regi: int <span class="Comment"># arr can be in reg or mem</span>
=> <span class="Constant">"69/multiply %"</span> regi <span class="Constant">" "</span> size-of(T) <span class="Constant">"/imm32 "</span> reg <span class="Constant">"/r32"</span>
var/reg: (offset T) <span class="Special"><-</span> compute-offset arr: (addr array T), idx: int <span class="Comment"># arr can be in reg or mem</span>
=> <span class="Constant">"69/multiply *(ebp+"</span> idx.stack-offset <span class="Constant">") "</span> size-of(T) <span class="Constant">"/imm32 "</span> reg <span class="Constant">"/r32"</span>
var/reg <span class="Special"><-</span> index arr/rega: (addr array T), o/rego: offset
=> <span class="Constant">"8d/copy-address *("</span> rega <span class="Constant">"+"</span> rego <span class="Constant">"+4) "</span> reg <span class="Constant">"/r32"</span>
Computing the length of an array is complex.
var/reg <span class="Special"><-</span> length arr/reg2: (addr array T)
| if T is byte (TODO)
=> <span class="Constant">"8b/-> *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
| if size-of(T) is <span class="Constant">4</span> or <span class="Constant">8</span> or <span class="Constant">16</span> or <span class="Constant">32</span> or <span class="Constant">64</span> or <span class="Constant">128</span>
=> <span class="Constant">"8b/-> *"</span> reg2 <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
<span class="Constant">"c1/shift 5/subop/logic-right %"</span> reg <span class="Constant">" "</span> log2(size-of(T)) <span class="Constant">"/imm8"</span>
| otherwise
x86 has no instruction to divide by a literal, so
we need up to <span class="Constant">3</span> extra registers! <span class="Constant">eax</span>/<span class="Constant">edx</span> for division and say <span class="Constant">ecx</span>
=> if reg is not <span class="Constant">eax</span>
<span class="Constant">"50/push-eax"</span>
if reg is not <span class="Constant">ecx</span>
<span class="Constant">"51/push-ecx"</span>
if reg is not <span class="Constant">edx</span>
<span class="Constant">"52/push-edx"</span>
<span class="Constant">"8b/-> *"</span> reg2 <span class="Constant">" eax/r32"</span>
<span class="Constant">"31/xor %edx 2/r32/edx"</span> <span class="Comment"># sign-extend, but array size can't be negative</span>
<span class="Constant">"b9/copy-to-ecx "</span> size-of(T) <span class="Constant">"/imm32"</span>
<span class="Constant">"f7 7/subop/idiv-eax-edx-by %ecx"</span>
if reg is not <span class="Constant">eax</span>
<span class="Constant">"89/<- %"</span> reg <span class="Constant">" 0/r32/eax"</span>
if reg is not <span class="Constant">edx</span>
<span class="Constant">"5a/pop-to-edx"</span>
if reg is not <span class="Constant">ecx</span>
<span class="Constant">"59/pop-to-ecx"</span>
if reg is not <span class="Constant">eax</span>
<span class="Constant">"58/pop-to-eax"</span>
<span class="Comment"># User-defined types</span>
If a record (product) type T was defined to have elements a, b, c, ... of
types T_a, T_b, T_c, ..., then accessing one of those elements f of type T_f:
var/reg: (addr T_f) <span class="Special"><-</span> get var2/reg2: (addr F), f
=> <span class="Constant">"8d/copy-address *("</span> reg2 <span class="Constant">"+"</span> offset(f) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
var/reg: (addr T_f) <span class="Special"><-</span> get var2: (addr F), f
=> <span class="Constant">"8d/copy-address *(ebp+"</span> var2.stack-offset <span class="Constant">"+"</span> offset(f) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
<span class="Comment"># Handles for safe access to the heap</span>
copy-handle-to dest: (handle T), src: (handle T)
=> <span class="Constant">"50/push-eax"</span>
<span class="Constant">"8b/-> *(ebp+"</span> src.stack-offset <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"89/<- *(ebp+"</span> dest.stack-offset <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"8b/-> *(ebp+"</span> src.stack-offset+<span class="Constant">4</span> <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"89/<- *(ebp+"</span> dest.stack-offset+<span class="Constant">4</span> <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"58/pop-to-eax"</span>
copy-handle-to *dest/reg: (addr handle T), src: (handle T)
=> <span class="Constant">"50/push-eax"</span>
<span class="Constant">"8b/-> *(ebp+"</span> src.stack-offset <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"89/<- *"</span> reg <span class="Constant">" 0/r32/eax"</span>
<span class="Constant">"8b/-> *(ebp+"</span> src.stack-offset+<span class="Constant">4</span> <span class="Constant">") 0/r32/eax"</span>
<span class="Constant">"89/<- *("</span> reg <span class="Constant">"+4) 0/r32/eax"</span>
<span class="Constant">"58/pop-to-eax"</span>
out/reg: (addr T) <span class="Special"><-</span> lookup in: (handle T)
=> <span class="Comment"># payload_allocid = in->address->allocid</span>
<span class="Constant">"8b/-> *(epb+"</span> (in.stack-offset+<span class="Constant">4</span>) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
<span class="Constant">"8b/-> *"</span> reg <span class="Constant">" "</span> reg <span class="Constant">"/r32"</span>
<span class="Comment"># if (payload_allocid != handle->allocid) abort</span>
<span class="Constant">"39/compare *(ebp+"</span> in.stack-offset <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
<span class="Constant">"0f 85/jump-if-!= $lookup:abort/disp32"</span>
<span class="Comment"># return payload</span>
<span class="Constant">"8b/-> *(epb+"</span> (in.stack-offset+<span class="Constant">4</span>) <span class="Constant">") "</span> reg <span class="Constant">"/r32"</span>
<span class="Constant">"81 0/subop/add %"</span> reg <span class="Constant">" 4/imm32"</span> <span class="Comment"># skip payload->allocid</span>
vim:ft=mu:nowrap:textwidth=<span class="Constant">0</span>
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